diff --git a/swad_changelog.h b/swad_changelog.h
index 564c709cb..9c9a42fc0 100644
--- a/swad_changelog.h
+++ b/swad_changelog.h
@@ -355,10 +355,11 @@ En OpenSWAD:
 ps2pdf source.ps destination.pdf
 */
 
-#define Log_PLATFORM_VERSION	"SWAD 18.8.16 (2018-10-28)"
+#define Log_PLATFORM_VERSION	"SWAD 18.8.17 (2018-10-28)"
 #define CSS_FILE		"swad18.4.css"
 #define JS_FILE			"swad17.17.1.js"
 /*
+	Version 18.8.17:  Oct 28, 2018  Some asprintf for database queries changed by internal function. (236116 lines)
 	Version 18.8.16:  Oct 28, 2018  Some asprintf for database queries changed by internal function. (236263 lines)
 	Version 18.8.15:  Oct 28, 2018  Some asprintf for database queries changed by internal function. (236425 lines)
 	Version 18.8.14:  Oct 28, 2018  Some asprintf for database queries changed by internal function. (236493 lines)
diff --git a/swad_database.c b/swad_database.c
index 6d1a183a3..3bc79ccdc 100644
--- a/swad_database.c
+++ b/swad_database.c
@@ -3331,17 +3331,6 @@ void DB_QueryDELETE_new (const char *MsgError)
       DB_ExitOnMySQLError (MsgError);
   }
 
-void DB_QueryDELETE_free (const char *Query,const char *MsgError)
-  {
-   int Result;
-
-   /***** Query database *****/
-   Result = mysql_query (&Gbl.mysql,Query);	// Returns 0 on success
-   free ((void *) Query);
-   if (Result)
-      DB_ExitOnMySQLError (MsgError);
-  }
-
 void DB_QueryDELETE (const char *Query,const char *MsgError)
   {
    /***** Query database *****/
diff --git a/swad_database.h b/swad_database.h
index 3a4091ed4..52f7854b7 100644
--- a/swad_database.h
+++ b/swad_database.h
@@ -58,7 +58,6 @@ void DB_QueryUPDATE_new (const char *MsgError);
 void DB_QueryUPDATE (const char *Query,const char *MsgError);
 
 void DB_QueryDELETE_new (const char *MsgError);
-void DB_QueryDELETE_free (const char *Query,const char *MsgError);
 void DB_QueryDELETE (const char *Query,const char *MsgError);
 
 void DB_Query_free (const char *Query,const char *MsgError);
diff --git a/swad_follow.c b/swad_follow.c
index ccc16a291..c8a0cf587 100644
--- a/swad_follow.c
+++ b/swad_follow.c
@@ -1203,11 +1203,8 @@ void Fol_GetNotifFollower (char SummaryStr[Ntf_MAX_BYTES_SUMMARY + 1],
 
 void Fol_RemoveUsrFromUsrFollow (long UsrCod)
   {
-   char *Query;
-
-   if (asprintf (&Query,"DELETE FROM usr_follow"
-	                " WHERE FollowerCod=%ld OR FollowedCod=%ld",
-	         UsrCod,UsrCod) < 0)
-            Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove user from followers and followed");
+   DB_BuildQuery ("DELETE FROM usr_follow"
+		  " WHERE FollowerCod=%ld OR FollowedCod=%ld",
+	          UsrCod,UsrCod);
+   DB_QueryDELETE_new ("can not remove user from followers and followed");
   }
diff --git a/swad_forum.c b/swad_forum.c
index 7d8f9c595..203ac1073 100644
--- a/swad_forum.c
+++ b/swad_forum.c
@@ -469,13 +469,9 @@ static bool For_GetIfPstIsEnabled (long PstCod)
 
 static void For_DeletePstFromDisabledPstTable (long PstCod)
   {
-   char *Query;
-
    /***** Remove post from disabled posts table *****/
-   if (asprintf (&Query,"DELETE FROM forum_disabled_post WHERE PstCod=%ld",
-                 PstCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not unban a post of a forum");
+   DB_BuildQuery ("DELETE FROM forum_disabled_post WHERE PstCod=%ld",PstCod);
+   DB_QueryDELETE_new ("can not unban a post of a forum");
   }
 
 /*****************************************************************************/
@@ -533,7 +529,6 @@ static long For_InsertForumPst (long ThrCod,long UsrCod,
 
 static bool For_RemoveForumPst (long PstCod,struct Image *Image)
   {
-   char *Query;
    long ThrCod;
    bool ThreadDeleted = false;
 
@@ -548,10 +543,8 @@ static bool For_RemoveForumPst (long PstCod,struct Image *Image)
      }
 
    /***** Delete post from forum post table *****/
-   if (asprintf (&Query,"DELETE FROM forum_post WHERE PstCod=%ld",
-                 PstCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a post from a forum");
+   DB_BuildQuery ("DELETE FROM forum_post WHERE PstCod=%ld",PstCod);
+   DB_QueryDELETE_new ("can not remove a post from a forum");
 
    /***** Delete the post from the table of disabled forum posts *****/
    For_DeletePstFromDisabledPstTable (PstCod);
@@ -615,8 +608,6 @@ static long For_InsertForumThread (long FirstPstCod)
 
 static void For_RemoveThreadOnly (long ThrCod)
   {
-   char *Query;
-
    /***** Indicate that this thread has not been read by anyone *****/
    For_DeleteThrFromReadThrs (ThrCod);
 
@@ -624,10 +615,8 @@ static void For_RemoveThreadOnly (long ThrCod)
    For_RemoveThrCodFromThrClipboard (ThrCod);
 
    /***** Delete thread from forum thread table *****/
-   if (asprintf (&Query,"DELETE FROM forum_thread WHERE ThrCod=%ld",
-                 ThrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a thread from a forum");
+   DB_BuildQuery ("DELETE FROM forum_thread WHERE ThrCod=%ld",ThrCod);
+   DB_QueryDELETE_new ("can not remove a thread from a forum");
   }
 
 /*****************************************************************************/
@@ -636,22 +625,17 @@ static void For_RemoveThreadOnly (long ThrCod)
 
 static void For_RemoveThreadAndItsPsts (long ThrCod)
   {
-   char *Query;
-
    /***** Delete banned posts in thread *****/
-   if (asprintf (&Query,"DELETE forum_disabled_post"
-			" FROM forum_post,forum_disabled_post"
-			" WHERE forum_post.ThrCod=%ld"
-			" AND forum_post.PstCod=forum_disabled_post.PstCod",
-                 ThrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not unban the posts of a thread of a forum");
+   DB_BuildQuery ("DELETE forum_disabled_post"
+		  " FROM forum_post,forum_disabled_post"
+		  " WHERE forum_post.ThrCod=%ld"
+		  " AND forum_post.PstCod=forum_disabled_post.PstCod",
+                  ThrCod);
+   DB_QueryDELETE_new ("can not unban the posts of a thread of a forum");
 
    /***** Delete thread posts *****/
-   if (asprintf (&Query,"DELETE FROM forum_post WHERE ThrCod=%ld",
-                 ThrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove the posts of a thread of a forum");
+   DB_BuildQuery ("DELETE FROM forum_post WHERE ThrCod=%ld",ThrCod);
+   DB_QueryDELETE_new ("can not remove the posts of a thread of a forum");
 
    /***** Delete thread from forum thread table *****/
    For_RemoveThreadOnly (ThrCod);
@@ -912,13 +896,9 @@ static time_t For_GetThrReadTime (long ThrCod)
 
 static void For_DeleteThrFromReadThrs (long ThrCod)
   {
-   char *Query;
-
    /***** Delete pairs ThrCod-UsrCod in forum_thr_read for a thread *****/
-   if (asprintf (&Query,"DELETE FROM forum_thr_read WHERE ThrCod=%ld",
-                 ThrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove the status of reading of a thread of a forum");
+   DB_BuildQuery ("DELETE FROM forum_thr_read WHERE ThrCod=%ld",ThrCod);
+   DB_QueryDELETE_new ("can not remove the status of reading of a thread of a forum");
   }
 
 /*****************************************************************************/
@@ -927,13 +907,9 @@ static void For_DeleteThrFromReadThrs (long ThrCod)
 
 void For_RemoveUsrFromReadThrs (long UsrCod)
   {
-   char *Query;
-
    /***** Delete pairs ThrCod-UsrCod in forum_thr_read for a user *****/
-   if (asprintf (&Query,"DELETE FROM forum_thr_read WHERE UsrCod=%ld",
-                 UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove the status of reading by a user of all the threads of a forum");
+   DB_BuildQuery ("DELETE FROM forum_thr_read WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not remove the status of reading by a user of all the threads of a forum");
   }
 
 /*****************************************************************************/
@@ -4439,14 +4415,11 @@ static void For_InsertThrInClipboard (long ThrCod)
 
 static void For_RemoveExpiredThrsClipboards (void)
   {
-   char *Query;
-
    /***** Remove all expired clipboards *****/
-   if (asprintf (&Query,"DELETE LOW_PRIORITY FROM forum_thr_clip"
-                        " WHERE TimeInsert<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
-                 Cfg_TIME_TO_DELETE_THREAD_CLIPBOARD) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove old threads from clipboards");
+   DB_BuildQuery ("DELETE LOW_PRIORITY FROM forum_thr_clip"
+		  " WHERE TimeInsert<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
+                  Cfg_TIME_TO_DELETE_THREAD_CLIPBOARD);
+   DB_QueryDELETE_new ("can not remove old threads from clipboards");
   }
 
 /*****************************************************************************/
@@ -4455,13 +4428,9 @@ static void For_RemoveExpiredThrsClipboards (void)
 
 static void For_RemoveThrCodFromThrClipboard (long ThrCod)
   {
-   char *Query;
-
    /***** Remove thread from thread clipboard *****/
-   if (asprintf (&Query,"DELETE FROM forum_thr_clip WHERE ThrCod=%ld",
-                 ThrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a thread from clipboard");
+   DB_BuildQuery ("DELETE FROM forum_thr_clip WHERE ThrCod=%ld",ThrCod);
+   DB_QueryDELETE_new ("can not remove a thread from clipboard");
   }
 
 /*****************************************************************************/
@@ -4470,13 +4439,9 @@ static void For_RemoveThrCodFromThrClipboard (long ThrCod)
 
 void For_RemoveUsrFromThrClipboard (long UsrCod)
   {
-   char *Query;
-
    /***** Remove clipboard of specified user *****/
-   if (asprintf (&Query,"DELETE FROM forum_thr_clip WHERE UsrCod=%ld",
-                 UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a thread from the clipboard of a user");
+   DB_BuildQuery ("DELETE FROM forum_thr_clip WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not remove a thread from the clipboard of a user");
   }
 
 /*****************************************************************************/
@@ -4499,64 +4464,59 @@ void For_RemoveForums (Sco_Scope_t Scope,long ForumLocation)
 	{For_FORUM_DEGREE_USRS,For_FORUM_DEGREE_TCHS},	// Sco_SCOPE_DEG
 	{For_FORUM_COURSE_USRS,For_FORUM_COURSE_TCHS},	// Sco_SCOPE_CRS
      };
-   char *Query;
 
    /***** Remove disabled posts *****/
-   if (asprintf (&Query,"DELETE FROM forum_disabled_post"
-			" USING forum_thread,forum_post,forum_disabled_post"
-			" WHERE"
-			" (forum_thread.ForumType=%u"
-			" OR"
-			" forum_thread.ForumType=%u)"
-			" AND forum_thread.Location=%ld"
-			" AND forum_thread.ThrCod=forum_post.ThrCod"
-			" AND forum_post.PstCod=forum_disabled_post.PstCod",
-	         ForumType[Scope].Usrs,
-	         ForumType[Scope].Tchs,
-	         ForumLocation) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove the disabled posts in forums");
+   DB_BuildQuery ("DELETE FROM forum_disabled_post"
+		  " USING forum_thread,forum_post,forum_disabled_post"
+		  " WHERE"
+		  " (forum_thread.ForumType=%u"
+		  " OR"
+		  " forum_thread.ForumType=%u)"
+		  " AND forum_thread.Location=%ld"
+		  " AND forum_thread.ThrCod=forum_post.ThrCod"
+		  " AND forum_post.PstCod=forum_disabled_post.PstCod",
+	          ForumType[Scope].Usrs,
+	          ForumType[Scope].Tchs,
+	          ForumLocation);
+   DB_QueryDELETE_new ("can not remove the disabled posts in forums");
 
    /***** Remove posts *****/
-   if (asprintf (&Query,"DELETE FROM forum_post"
-			" USING forum_thread,forum_post"
-			" WHERE"
-			" (forum_thread.ForumType=%u"
-			" OR"
-			" forum_thread.ForumType=%u)"
-			" AND forum_thread.Location=%ld"
-			" AND forum_thread.ThrCod=forum_post.ThrCod",
-	         ForumType[Scope].Usrs,
-	         ForumType[Scope].Tchs,
-	         ForumLocation) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove posts in forums");
+   DB_BuildQuery ("DELETE FROM forum_post"
+		  " USING forum_thread,forum_post"
+		  " WHERE"
+		  " (forum_thread.ForumType=%u"
+		  " OR"
+		  " forum_thread.ForumType=%u)"
+		  " AND forum_thread.Location=%ld"
+		  " AND forum_thread.ThrCod=forum_post.ThrCod",
+	          ForumType[Scope].Usrs,
+	          ForumType[Scope].Tchs,
+	          ForumLocation);
+   DB_QueryDELETE_new ("can not remove posts in forums");
 
    /***** Remove threads read *****/
-   if (asprintf (&Query,"DELETE FROM forum_thr_read"
-			" USING forum_thread,forum_thr_read"
-			" WHERE"
-			" (forum_thread.ForumType=%u"
-			" OR"
-			" forum_thread.ForumType=%u)"
-			" AND forum_thread.Location=%ld"
-			" AND forum_thread.ThrCod=forum_thr_read.ThrCod",
-	         ForumType[Scope].Usrs,
-	         ForumType[Scope].Tchs,
-	         ForumLocation) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove read threads in forums");
+   DB_BuildQuery ("DELETE FROM forum_thr_read"
+		  " USING forum_thread,forum_thr_read"
+		  " WHERE"
+		  " (forum_thread.ForumType=%u"
+		  " OR"
+		  " forum_thread.ForumType=%u)"
+		  " AND forum_thread.Location=%ld"
+		  " AND forum_thread.ThrCod=forum_thr_read.ThrCod",
+	          ForumType[Scope].Usrs,
+	          ForumType[Scope].Tchs,
+	          ForumLocation);
+   DB_QueryDELETE_new ("can not remove read threads in forums");
 
    /***** Remove threads *****/
-   if (asprintf (&Query,"DELETE FROM forum_thread"
-			" WHERE"
-			" (forum_thread.ForumType=%u"
-			" OR"
-			" forum_thread.ForumType=%u)"
-			" AND Location=%ld",
-	         ForumType[Scope].Usrs,
-	         ForumType[Scope].Tchs,
-	         ForumLocation) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove threads in forums");
+   DB_BuildQuery ("DELETE FROM forum_thread"
+		  " WHERE"
+		  " (forum_thread.ForumType=%u"
+		  " OR"
+		  " forum_thread.ForumType=%u)"
+		  " AND Location=%ld",
+	          ForumType[Scope].Usrs,
+	          ForumType[Scope].Tchs,
+	          ForumLocation);
+   DB_QueryDELETE_new ("can not remove threads in forums");
   }
diff --git a/swad_game.c b/swad_game.c
index 8f9f44970..0457a3ebb 100644
--- a/swad_game.c
+++ b/swad_game.c
@@ -1512,7 +1512,6 @@ void Gam_AskRemGame (void)
 void Gam_RemoveGame (void)
   {
    extern const char *Txt_Game_X_removed;
-   char *Query;
    struct Game Game;
 
    /***** Get game code *****/
@@ -1525,26 +1524,19 @@ void Gam_RemoveGame (void)
       Lay_ShowErrorAndExit ("You can not remove this game.");
 
    /***** Remove all the users in this game *****/
-   if (asprintf (&Query,"DELETE FROM gam_users WHERE GamCod=%ld",
-                 Game.GamCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove users who are answered a game");
+   DB_BuildQuery ("DELETE FROM gam_users WHERE GamCod=%ld",Game.GamCod);
+   DB_QueryDELETE_new ("can not remove users who are answered a game");
 
    /***** Remove all the questions in this game *****/
-   if (asprintf (&Query,"DELETE FROM gam_questions"
-                        " WHERE GamCod=%ld",
-                 Game.GamCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove questions of a game");
+   DB_BuildQuery ("DELETE FROM gam_questions WHERE GamCod=%ld",Game.GamCod);
+   DB_QueryDELETE_new ("can not remove questions of a game");
 
    /***** Remove all the groups of this game *****/
    Gam_RemoveAllTheGrpsAssociatedToAndGame (Game.GamCod);
 
    /***** Remove game *****/
-   if (asprintf (&Query,"DELETE FROM games WHERE GamCod=%ld",
-                 Game.GamCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove game");
+   DB_BuildQuery ("DELETE FROM games WHERE GamCod=%ld",Game.GamCod);
+   DB_QueryDELETE_new ("can not remove game");
 
    /***** Write message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
@@ -1614,7 +1606,6 @@ static void Gam_PutButtonToResetGame (void)
 void Gam_ResetGame (void)
   {
    extern const char *Txt_Game_X_reset;
-   char *Query;
    struct Game Game;
 
    /***** Get game code *****/
@@ -1627,10 +1618,8 @@ void Gam_ResetGame (void)
       Lay_ShowErrorAndExit ("You can not reset this game.");
 
    /***** Remove all the users in this game *****/
-   if (asprintf (&Query,"DELETE FROM gam_users WHERE GamCod=%ld",
-                 Game.GamCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove users who are answered a game");
+   DB_BuildQuery ("DELETE FROM gam_users WHERE GamCod=%ld",Game.GamCod);
+   DB_QueryDELETE_new ("can not remove users who are answered a game");
 
    /***** Reset all the answers in this game *****/
    DB_BuildQuery ("UPDATE gam_answers,gam_questions SET gam_answers.NumUsrs=0"
@@ -2283,13 +2272,9 @@ bool Gam_CheckIfGamIsAssociatedToGrp (long GamCod,long GrpCod)
 
 static void Gam_RemoveAllTheGrpsAssociatedToAndGame (long GamCod)
   {
-   char *Query;
-
    /***** Remove groups of the game *****/
-   if (asprintf (&Query,"DELETE FROM gam_grp WHERE GamCod=%ld",
-                 GamCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove the groups associated to a game");
+   DB_BuildQuery ("DELETE FROM gam_grp WHERE GamCod=%ld",GamCod);
+   DB_QueryDELETE_new ("can not remove the groups associated to a game");
   }
 
 /*****************************************************************************/
@@ -2298,14 +2283,10 @@ static void Gam_RemoveAllTheGrpsAssociatedToAndGame (long GamCod)
 
 void Gam_RemoveGroup (long GrpCod)
   {
-   char *Query;
-
    /***** Remove group from all the games *****/
-   if (asprintf (&Query,"DELETE FROM gam_grp WHERE GrpCod=%ld",
-	         GrpCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove group"
-	                      " from the associations between games and groups");
+   DB_BuildQuery ("DELETE FROM gam_grp WHERE GrpCod=%ld",GrpCod);
+   DB_QueryDELETE_new ("can not remove group"
+	               " from the associations between games and groups");
   }
 
 /*****************************************************************************/
@@ -2314,16 +2295,13 @@ void Gam_RemoveGroup (long GrpCod)
 
 void Gam_RemoveGroupsOfType (long GrpTypCod)
   {
-   char *Query;
-
    /***** Remove group from all the games *****/
-   if (asprintf (&Query,"DELETE FROM gam_grp USING crs_grp,gam_grp"
-			" WHERE crs_grp.GrpTypCod=%ld"
-			" AND crs_grp.GrpCod=gam_grp.GrpCod",
-                 GrpTypCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove groups of a type"
-	                      " from the associations between games and groups");
+   DB_BuildQuery ("DELETE FROM gam_grp USING crs_grp,gam_grp"
+		  " WHERE crs_grp.GrpTypCod=%ld"
+		  " AND crs_grp.GrpCod=gam_grp.GrpCod",
+                  GrpTypCod);
+   DB_QueryDELETE_new ("can not remove groups of a type"
+	               " from the associations between games and groups");
   }
 
 /*****************************************************************************/
@@ -2423,53 +2401,47 @@ static void Gam_GetAndWriteNamesOfGrpsAssociatedToGame (struct Game *Game)
 void Gam_RemoveGames (Sco_Scope_t Scope,long Cod)
   {
    extern const char *Sco_ScopeDB[Sco_NUM_SCOPES];
-   char *Query;
 
    /***** Remove all the users in course games *****/
-   if (asprintf (&Query,"DELETE FROM gam_users"
-			" USING games,gam_users"
-			" WHERE games.Scope='%s' AND games.Cod=%ld"
-			" AND games.GamCod=gam_users.GamCod",
-                 Sco_ScopeDB[Scope],Cod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove users"
-	                      " who had answered games in a place on the hierarchy");
+   DB_BuildQuery ("DELETE FROM gam_users"
+		  " USING games,gam_users"
+		  " WHERE games.Scope='%s' AND games.Cod=%ld"
+		  " AND games.GamCod=gam_users.GamCod",
+                  Sco_ScopeDB[Scope],Cod);
+   DB_QueryDELETE_new ("can not remove users"
+	               " who had answered games in a place on the hierarchy");
 
    /***** Remove all the answers in course games *****/
-   if (asprintf (&Query,"DELETE FROM gam_answers"
-			" USING games,gam_questions,gam_answers"
-			" WHERE games.Scope='%s' AND games.Cod=%ld"
-			" AND games.GamCod=gam_questions.GamCod"
-			" AND gam_questions.QstCod=gam_answers.QstCod",
-                 Sco_ScopeDB[Scope],Cod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove answers of games in a place on the hierarchy");
+   DB_BuildQuery ("DELETE FROM gam_answers"
+		  " USING games,gam_questions,gam_answers"
+		  " WHERE games.Scope='%s' AND games.Cod=%ld"
+		  " AND games.GamCod=gam_questions.GamCod"
+		  " AND gam_questions.QstCod=gam_answers.QstCod",
+                  Sco_ScopeDB[Scope],Cod);
+   DB_QueryDELETE_new ("can not remove answers of games in a place on the hierarchy");
 
    /***** Remove all the questions in course games *****/
-   if (asprintf (&Query,"DELETE FROM gam_questions"
-			" USING games,gam_questions"
-			" WHERE games.Scope='%s' AND games.Cod=%ld"
-			" AND games.GamCod=gam_questions.GamCod",
-                 Sco_ScopeDB[Scope],Cod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove questions of games in a place on the hierarchy");
+   DB_BuildQuery ("DELETE FROM gam_questions"
+		  " USING games,gam_questions"
+		  " WHERE games.Scope='%s' AND games.Cod=%ld"
+		  " AND games.GamCod=gam_questions.GamCod",
+                  Sco_ScopeDB[Scope],Cod);
+   DB_QueryDELETE_new ("can not remove questions of games in a place on the hierarchy");
 
    /***** Remove groups *****/
-   if (asprintf (&Query,"DELETE FROM gam_grp"
-			" USING games,gam_grp"
-			" WHERE games.Scope='%s' AND games.Cod=%ld"
-			" AND games.GamCod=gam_grp.GamCod",
-                 Sco_ScopeDB[Scope],Cod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove all the groups"
-	                      " associated to games of a course");
+   DB_BuildQuery ("DELETE FROM gam_grp"
+		  " USING games,gam_grp"
+		  " WHERE games.Scope='%s' AND games.Cod=%ld"
+		  " AND games.GamCod=gam_grp.GamCod",
+                  Sco_ScopeDB[Scope],Cod);
+   DB_QueryDELETE_new ("can not remove all the groups"
+	               " associated to games of a course");
 
    /***** Remove course games *****/
-   if (asprintf (&Query,"DELETE FROM games"
-	                " WHERE Scope='%s' AND Cod=%ld",
-                 Sco_ScopeDB[Scope],Cod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove all the games in a place on the hierarchy");
+   DB_BuildQuery ("DELETE FROM games"
+		  " WHERE Scope='%s' AND Cod=%ld",
+                  Sco_ScopeDB[Scope],Cod);
+   DB_QueryDELETE_new ("can not remove all the games in a place on the hierarchy");
   }
 
 /*****************************************************************************/
@@ -2575,13 +2547,9 @@ static unsigned Gam_GetParamQstInd (void)
 
 static void Gam_RemAnswersOfAQuestion (long QstCod)
   {
-   char *Query;
-
    /***** Remove answers *****/
-   if (asprintf (&Query,"DELETE FROM gam_answers WHERE QstCod=%ld",
-                 QstCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove the answers of a question");
+   DB_BuildQuery ("DELETE FROM gam_answers WHERE QstCod=%ld",QstCod);
+   DB_QueryDELETE_new ("can not remove the answers of a question");
   }
 
 /*****************************************************************************/
diff --git a/swad_group.c b/swad_group.c
index 47aa2166f..42398fbfb 100644
--- a/swad_group.c
+++ b/swad_group.c
@@ -1210,18 +1210,16 @@ unsigned Grp_RemoveUsrFromGroups (struct UsrData *UsrDat,struct ListCodGrps *Lst
 
 void Grp_RemUsrFromAllGrpsInCrs (long UsrCod,long CrsCod)
   {
-   char *Query;
    bool ItsMe = Usr_ItsMe (UsrCod);
 
    /***** Remove user from all the groups of the course *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp_usr"
-			" WHERE UsrCod=%ld AND GrpCod IN"
-			" (SELECT crs_grp.GrpCod FROM crs_grp_types,crs_grp"
-			" WHERE crs_grp_types.CrsCod=%ld"
-			" AND crs_grp_types.GrpTypCod=crs_grp.GrpTypCod)",
-                 UsrCod,CrsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a user from all groups of a course");
+   DB_BuildQuery ("DELETE FROM crs_grp_usr"
+		  " WHERE UsrCod=%ld AND GrpCod IN"
+		  " (SELECT crs_grp.GrpCod FROM crs_grp_types,crs_grp"
+		  " WHERE crs_grp_types.CrsCod=%ld"
+		  " AND crs_grp_types.GrpTypCod=crs_grp.GrpTypCod)",
+                  UsrCod,CrsCod);
+   DB_QueryDELETE_new ("can not remove a user from all groups of a course");
 
    /***** Flush caches *****/
    Grp_FlushCacheUsrSharesAnyOfMyGrpsInCurrentCrs ();
@@ -1235,14 +1233,11 @@ void Grp_RemUsrFromAllGrpsInCrs (long UsrCod,long CrsCod)
 
 void Grp_RemUsrFromAllGrps (long UsrCod)
   {
-   char *Query;
    bool ItsMe = Usr_ItsMe (UsrCod);
 
    /***** Remove user from all groups *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp_usr WHERE UsrCod=%ld",
-                 UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a user from the groups he/she belongs to");
+   DB_BuildQuery ("DELETE FROM crs_grp_usr WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not remove a user from the groups he/she belongs to");
 
    /***** Flush caches *****/
    Grp_FlushCacheUsrSharesAnyOfMyGrpsInCurrentCrs ();
@@ -1256,15 +1251,13 @@ void Grp_RemUsrFromAllGrps (long UsrCod)
 
 static void Grp_RemoveUsrFromGroup (long UsrCod,long GrpCod)
   {
-   char *Query;
    bool ItsMe = Usr_ItsMe (UsrCod);
 
    /***** Remove user from group *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp_usr"
-	                " WHERE GrpCod=%ld AND UsrCod=%ld",
-                 GrpCod,UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a user from a group");
+   DB_BuildQuery ("DELETE FROM crs_grp_usr"
+		  " WHERE GrpCod=%ld AND UsrCod=%ld",
+                  GrpCod,UsrCod);
+   DB_QueryDELETE_new ("can not remove a user from a group");
 
    /***** Flush caches *****/
    Grp_FlushCacheUsrSharesAnyOfMyGrpsInCurrentCrs ();
@@ -4018,7 +4011,6 @@ void Grp_RemoveGroup (void)
 static void Grp_RemoveGroupTypeCompletely (void)
   {
    extern const char *Txt_Type_of_group_X_removed;
-   char *Query;
 
    /***** Get name and type of the group from database *****/
    Grp_GetDataOfGroupTypeByCod (&Gbl.CurrentCrs.Grps.GrpTyp);
@@ -4043,23 +4035,20 @@ static void Grp_RemoveGroupTypeCompletely (void)
    DB_QueryUPDATE_new ("can not update all groups of a type in course timetable");
 
    /***** Remove all the students in groups of this type *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp_usr WHERE GrpCod IN"
-			" (SELECT GrpCod FROM crs_grp WHERE GrpTypCod=%ld)",
-                 Gbl.CurrentCrs.Grps.GrpTyp.GrpTypCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove users from all groups of a type");
+   DB_BuildQuery ("DELETE FROM crs_grp_usr WHERE GrpCod IN"
+		  " (SELECT GrpCod FROM crs_grp WHERE GrpTypCod=%ld)",
+                  Gbl.CurrentCrs.Grps.GrpTyp.GrpTypCod);
+   DB_QueryDELETE_new ("can not remove users from all groups of a type");
 
    /***** Remove all the groups of this type *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp WHERE GrpTypCod=%ld",
-                 Gbl.CurrentCrs.Grps.GrpTyp.GrpTypCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove groups of a type");
+   DB_BuildQuery ("DELETE FROM crs_grp WHERE GrpTypCod=%ld",
+                  Gbl.CurrentCrs.Grps.GrpTyp.GrpTypCod);
+   DB_QueryDELETE_new ("can not remove groups of a type");
 
    /***** Remove the group type *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp_types WHERE GrpTypCod=%ld",
-                 Gbl.CurrentCrs.Grps.GrpTyp.GrpTypCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a type of group");
+   DB_BuildQuery ("DELETE FROM crs_grp_types WHERE GrpTypCod=%ld",
+                  Gbl.CurrentCrs.Grps.GrpTyp.GrpTypCod);
+   DB_QueryDELETE_new ("can not remove a type of group");
 
    /***** Create message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
@@ -4079,7 +4068,6 @@ static void Grp_RemoveGroupCompletely (void)
   {
    extern const char *Txt_Group_X_removed;
    struct GroupData GrpDat;
-   char *Query;
 
    /***** Get name and type of the group from database *****/
    GrpDat.GrpCod = Gbl.CurrentCrs.Grps.GrpCod;
@@ -4103,16 +4091,14 @@ static void Grp_RemoveGroupCompletely (void)
    DB_QueryUPDATE_new ("can not update a group in course timetable");
 
    /***** Remove all the students in this group *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp_usr WHERE GrpCod=%ld",
-                 Gbl.CurrentCrs.Grps.GrpCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove users from a group");
+   DB_BuildQuery ("DELETE FROM crs_grp_usr WHERE GrpCod=%ld",
+                  Gbl.CurrentCrs.Grps.GrpCod);
+   DB_QueryDELETE_new ("can not remove users from a group");
 
    /***** Remove the group *****/
-   if (asprintf (&Query,"DELETE FROM crs_grp WHERE GrpCod=%ld",
-                 Gbl.CurrentCrs.Grps.GrpCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a group");
+   DB_BuildQuery ("DELETE FROM crs_grp WHERE GrpCod=%ld",
+                  Gbl.CurrentCrs.Grps.GrpCod);
+   DB_QueryDELETE_new ("can not remove a group");
 
    /***** Create message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
diff --git a/swad_holiday.c b/swad_holiday.c
index b5582cef5..0ca53a814 100644
--- a/swad_holiday.c
+++ b/swad_holiday.c
@@ -639,7 +639,6 @@ long Hld_GetParamHldCod (void)
 void Hld_RemoveHoliday1 (void)
   {
    extern const char *Txt_Holiday_X_removed;
-   char *Query;
    struct Holiday Hld;
 
    /***** Get holiday code *****/
@@ -650,10 +649,8 @@ void Hld_RemoveHoliday1 (void)
    Hld_GetDataOfHolidayByCod (&Hld);
 
    /***** Remove holiday *****/
-   if (asprintf (&Query,"DELETE FROM holidays WHERE HldCod=%ld",
-                 Hld.HldCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a holiday");
+   DB_BuildQuery ("DELETE FROM holidays WHERE HldCod=%ld",Hld.HldCod);
+   DB_QueryDELETE_new ("can not remove a holiday");
 
    /***** Write message to show the change made *****/
    Gbl.Alert.Type = Ale_SUCCESS;
diff --git a/swad_info.c b/swad_info.c
index f6df9d84e..a715cd6af 100644
--- a/swad_info.c
+++ b/swad_info.c
@@ -741,14 +741,11 @@ static void Inf_SetIHaveReadIntoDB (bool IHaveRead)
 
 void Inf_RemoveUsrFromCrsInfoRead (long UsrCod,long CrsCod)
   {
-   char *Query;
-
    /***** Remove user's status about reading of course information *****/
-   if (asprintf (&Query,"DELETE FROM crs_info_read"
-                        " WHERE UsrCod=%ld AND CrsCod=%ld",
-                 UsrCod,CrsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not set that I have not read course info");
+   DB_BuildQuery ("DELETE FROM crs_info_read"
+		  " WHERE UsrCod=%ld AND CrsCod=%ld",
+                  UsrCod,CrsCod);
+   DB_QueryDELETE_new ("can not set that I have not read course info");
   }
 
 /*****************************************************************************/
diff --git a/swad_institution.c b/swad_institution.c
index 654b645d1..66ad516b2 100644
--- a/swad_institution.c
+++ b/swad_institution.c
@@ -1685,7 +1685,6 @@ void Ins_RemoveInstitution (void)
   {
    extern const char *Txt_To_remove_an_institution_you_must_first_remove_all_centres_and_users_in_the_institution;
    extern const char *Txt_Institution_X_removed;
-   char *Query;
    struct Instit Ins;
    char PathIns[PATH_MAX + 1];
 
@@ -1722,10 +1721,8 @@ void Ins_RemoveInstitution (void)
       Fil_RemoveTree (PathIns);
 
       /***** Remove institution *****/
-      if (asprintf (&Query,"DELETE FROM institutions WHERE InsCod=%ld",
-                    Ins.InsCod) < 0)
-         Lay_NotEnoughMemoryExit ();
-      DB_QueryDELETE_free (Query,"can not remove an institution");
+      DB_BuildQuery ("DELETE FROM institutions WHERE InsCod=%ld",Ins.InsCod);
+      DB_QueryDELETE_new ("can not remove an institution");
 
       /***** Flush caches *****/
       Ins_FlushCacheShortNameOfInstitution ();
diff --git a/swad_link.c b/swad_link.c
index 4f527593c..db2a41bca 100644
--- a/swad_link.c
+++ b/swad_link.c
@@ -487,7 +487,6 @@ long Lnk_GetParamLnkCod (void)
 void Lnk_RemoveLink (void)
   {
    extern const char *Txt_Link_X_removed;
-   char *Query;
    struct Link Lnk;
 
    /***** Get link code *****/
@@ -498,10 +497,8 @@ void Lnk_RemoveLink (void)
    Lnk_GetDataOfLinkByCod (&Lnk);
 
    /***** Remove link *****/
-   if (asprintf (&Query,"DELETE FROM links WHERE LnkCod=%ld",
-                 Lnk.LnkCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove an institutional link");
+   DB_BuildQuery ("DELETE FROM links WHERE LnkCod=%ld",Lnk.LnkCod);
+   DB_QueryDELETE_new ("can not remove an institutional link");
 
    /***** Write message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
diff --git a/swad_mail.c b/swad_mail.c
index 592fbca2d..028e43464 100644
--- a/swad_mail.c
+++ b/swad_mail.c
@@ -543,7 +543,6 @@ long Mai_GetParamMaiCod (void)
 void Mai_RemoveMailDomain (void)
   {
    extern const char *Txt_Email_domain_X_removed;
-   char *Query;
    struct Mail Mai;
 
    /***** Get mail code *****/
@@ -554,10 +553,8 @@ void Mai_RemoveMailDomain (void)
    Mai_GetDataOfMailDomainByCod (&Mai);
 
    /***** Remove mail *****/
-   if (asprintf (&Query,"DELETE FROM mail_domains WHERE MaiCod=%ld",
-                 Mai.MaiCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a mail domain");
+   DB_BuildQuery ("DELETE FROM mail_domains WHERE MaiCod=%ld",Mai.MaiCod);
+   DB_QueryDELETE_new ("can not remove a mail domain");
 
    /***** Write message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
@@ -1622,8 +1619,6 @@ static void Mai_NewUsrEmail (struct UsrData *UsrDat,bool ItsMe)
 
 bool Mai_UpdateEmailInDB (const struct UsrData *UsrDat,const char NewEmail[Cns_MAX_BYTES_EMAIL_ADDRESS + 1])
   {
-   char *Query;
-
    /***** Check if the new email matches any of the confirmed emails of other users *****/
    DB_BuildQuery ("SELECT COUNT(*) FROM usr_emails"
 		  " WHERE E_mail='%s' AND Confirmed='Y'"
@@ -1633,18 +1628,16 @@ bool Mai_UpdateEmailInDB (const struct UsrData *UsrDat,const char NewEmail[Cns_M
       return false;	// Don't update
 
    /***** Delete email (not confirmed) for other users *****/
-   if (asprintf (&Query,"DELETE FROM pending_emails"
-                        " WHERE E_mail='%s' AND UsrCod<>%ld",
-	         NewEmail,UsrDat->UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove pending email for other users");
+   DB_BuildQuery ("DELETE FROM pending_emails"
+		  " WHERE E_mail='%s' AND UsrCod<>%ld",
+	          NewEmail,UsrDat->UsrCod);
+   DB_QueryDELETE_new ("can not remove pending email for other users");
 
-   if (asprintf (&Query,"DELETE FROM usr_emails"
-                        " WHERE E_mail='%s' AND Confirmed='N'"
-		        " AND UsrCod<>%ld",
-	         NewEmail,UsrDat->UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove not confirmed email for other users");
+   DB_BuildQuery ("DELETE FROM usr_emails"
+		  " WHERE E_mail='%s' AND Confirmed='N'"
+		  " AND UsrCod<>%ld",
+	          NewEmail,UsrDat->UsrCod);
+   DB_QueryDELETE_new ("can not remove not confirmed email for other users");
 
    /***** Update email in database *****/
    DB_BuildQuery ("REPLACE INTO usr_emails"
@@ -1771,14 +1764,11 @@ bool Mai_SendMailMsgToConfirmEmail (void)
 static void Mai_InsertMailKey (const char Email[Cns_MAX_BYTES_EMAIL_ADDRESS + 1],
                                const char MailKey[Mai_LENGTH_EMAIL_CONFIRM_KEY + 1])
   {
-   char *Query;
-
    /***** Remove expired pending emails from database *****/
-   if (asprintf (&Query,"DELETE FROM pending_emails"
-                        " WHERE DateAndTime<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
-                 Cfg_TIME_TO_DELETE_OLD_PENDING_EMAILS) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove old pending mail keys");
+   DB_BuildQuery ("DELETE FROM pending_emails"
+		  " WHERE DateAndTime<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
+                  Cfg_TIME_TO_DELETE_OLD_PENDING_EMAILS);
+   DB_QueryDELETE_new ("can not remove old pending mail keys");
 
    /***** Insert mail key in database *****/
    DB_BuildQuery ("INSERT INTO pending_emails"
@@ -1801,7 +1791,6 @@ void Mai_ConfirmEmail (void)
    extern const char *Txt_The_email_X_has_been_confirmed;
    extern const char *Txt_The_email_address_has_not_been_confirmed;
    extern const char *Txt_Failed_email_confirmation_key;
-   char *Query;
    MYSQL_RES *mysql_res;
    MYSQL_ROW row;
    char MailKey[Mai_LENGTH_EMAIL_CONFIRM_KEY + 1];
@@ -1837,10 +1826,8 @@ void Mai_ConfirmEmail (void)
    if (KeyIsCorrect)
      {
       /***** Delete this key *****/
-      if (asprintf (&Query,"DELETE FROM pending_emails WHERE MailKey='%s'",
-                    MailKey) < 0)
-         Lay_NotEnoughMemoryExit ();
-      DB_QueryDELETE_free (Query,"can not remove an email key");
+      DB_BuildQuery ("DELETE FROM pending_emails WHERE MailKey='%s'",MailKey);
+      DB_QueryDELETE_new ("can not remove an email key");
 
       /***** Check user's code and email
              and get if email is already confirmed *****/
diff --git a/swad_notice.c b/swad_notice.c
index 6a638ecfa..843d6aa5b 100644
--- a/swad_notice.c
+++ b/swad_notice.c
@@ -292,7 +292,6 @@ void Not_RequestRemNotice (void)
 
 void Not_RemoveNotice (void)
   {
-   char *Query;
    long NotCod;
 
    /***** Get the code of the notice to remove *****/
@@ -309,11 +308,10 @@ void Not_RemoveNotice (void)
    DB_QueryINSERT_new ("can not remove notice");
 
    /* Remove notice */
-   if (asprintf (&Query,"DELETE FROM notices"
-			" WHERE NotCod=%ld AND CrsCod=%ld",
-                 NotCod,Gbl.CurrentCrs.Crs.CrsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove notice");
+   DB_BuildQuery ("DELETE FROM notices"
+		  " WHERE NotCod=%ld AND CrsCod=%ld",
+                  NotCod,Gbl.CurrentCrs.Crs.CrsCod);
+   DB_QueryDELETE_new ("can not remove notice");
 
    /***** Mark possible notifications as removed *****/
    Ntf_MarkNotifAsRemoved (Ntf_EVENT_NOTICE,NotCod);
diff --git a/swad_notification.c b/swad_notification.c
index 7bca9805d..f8c760d6e 100644
--- a/swad_notification.c
+++ b/swad_notification.c
@@ -1506,7 +1506,6 @@ static void Ntf_UpdateMyLastAccessToNotifications (void)
 
 void Ntf_SendPendingNotifByEMailToAllUsrs (void)
   {
-   char *Query;
    MYSQL_RES *mysql_res;
    MYSQL_ROW row;
    unsigned long NumRow,NumRows;
@@ -1559,11 +1558,10 @@ void Ntf_SendPendingNotifByEMailToAllUsrs (void)
    DB_FreeMySQLResult (&mysql_res);
 
    /***** Delete old notifications ******/
-   if (asprintf (&Query,"DELETE LOW_PRIORITY FROM notif"
-                        " WHERE TimeNotif<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
-                 Cfg_TIME_TO_DELETE_OLD_NOTIF) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove old notifications");
+   DB_BuildQuery ("DELETE LOW_PRIORITY FROM notif"
+		  " WHERE TimeNotif<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
+                  Cfg_TIME_TO_DELETE_OLD_NOTIF);
+   DB_QueryDELETE_new ("can not remove old notifications");
   }
 
 /*****************************************************************************/
@@ -2101,12 +2099,8 @@ static unsigned Ntf_GetNumberOfMyNewUnseenNtfs (void)
 
 void Ntf_RemoveUsrNtfs (long ToUsrCod)
   {
-   char *Query;
-
    /***** Delete notifications of a user ******/
-   if (asprintf (&Query,"DELETE LOW_PRIORITY FROM notif"
-	                " WHERE ToUsrCod=%ld",
-                 ToUsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove notifications of a user");
+   DB_BuildQuery ("DELETE LOW_PRIORITY FROM notif WHERE ToUsrCod=%ld",
+                  ToUsrCod);
+   DB_QueryDELETE_new ("can not remove notifications of a user");
   }
diff --git a/swad_photo.c b/swad_photo.c
index 20d1a1770..0b7e621d9 100644
--- a/swad_photo.c
+++ b/swad_photo.c
@@ -1030,12 +1030,8 @@ unsigned Pho_UpdateMyClicksWithoutPhoto (void)
 
 void Pho_RemoveUsrFromTableClicksWithoutPhoto (long UsrCod)
   {
-   char *Query;
-
-   if (asprintf (&Query,"DELETE FROM clicks_without_photo WHERE UsrCod=%ld",
-	         UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a user from the list of users without photo");
+   DB_BuildQuery ("DELETE FROM clicks_without_photo WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not remove a user from the list of users without photo");
   }
 
 /*****************************************************************************/
@@ -1503,12 +1499,9 @@ static long Pho_GetDegWithAvgPhotoLeastRecentlyUpdated (void)
 
 void Pho_RemoveObsoleteStatDegrees (void)
   {
-   char *Query;
-
-   if (asprintf (&Query,"DELETE FROM sta_degrees"
-			" WHERE DegCod NOT IN (SELECT DegCod FROM degrees)") < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove old degrees from stats");
+   DB_BuildQuery ("DELETE FROM sta_degrees"
+		  " WHERE DegCod NOT IN (SELECT DegCod FROM degrees)");
+   DB_QueryDELETE_new ("can not remove old degrees from stats");
   }
 
 /*****************************************************************************/
diff --git a/swad_place.c b/swad_place.c
index 9f4af94d0..485812e22 100644
--- a/swad_place.c
+++ b/swad_place.c
@@ -556,7 +556,6 @@ void Plc_RemovePlace (void)
   {
    extern const char *Txt_To_remove_a_place_you_must_first_remove_all_centres_of_that_place;
    extern const char *Txt_Place_X_removed;
-   char *Query;
    struct Place Plc;
 
    /***** Get place code *****/
@@ -572,10 +571,8 @@ void Plc_RemovePlace (void)
    else			// Place has no centres ==> remove it
      {
       /***** Remove place *****/
-      if (asprintf (&Query,"DELETE FROM places WHERE PlcCod=%ld",
-	            Plc.PlcCod) < 0)
-         Lay_NotEnoughMemoryExit ();
-      DB_QueryDELETE_free (Query,"can not remove a place");
+      DB_BuildQuery ("DELETE FROM places WHERE PlcCod=%ld",Plc.PlcCod);
+      DB_QueryDELETE_new ("can not remove a place");
 
       /***** Write message to show the change made *****/
       snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
diff --git a/swad_plugin.c b/swad_plugin.c
index efff5f02d..821b1521c 100644
--- a/swad_plugin.c
+++ b/swad_plugin.c
@@ -486,7 +486,6 @@ long Plg_GetParamPlgCod (void)
 void Plg_RemovePlugin (void)
   {
    extern const char *Txt_Plugin_X_removed;
-   char *Query;
    struct Plugin Plg;
 
    /***** Get plugin code *****/
@@ -497,10 +496,8 @@ void Plg_RemovePlugin (void)
    Plg_GetDataOfPluginByCod (&Plg);
 
    /***** Remove plugin *****/
-   if (asprintf (&Query,"DELETE FROM plugins WHERE PlgCod=%ld",
-                 Plg.PlgCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove a plugin");
+   DB_BuildQuery ("DELETE FROM plugins WHERE PlgCod=%ld",Plg.PlgCod);
+   DB_QueryDELETE_new ("can not remove a plugin");
 
    /***** Write message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
diff --git a/swad_preference.c b/swad_preference.c
index 321d23500..279a51977 100644
--- a/swad_preference.c
+++ b/swad_preference.c
@@ -216,14 +216,11 @@ void Pre_SetPrefsFromIP (void)
 
 void Pre_RemoveOldPrefsFromIP (void)
   {
-   char *Query;
-
    /***** Remove old preferences *****/
-   if (asprintf (&Query,"DELETE LOW_PRIORITY FROM IP_prefs"
-			" WHERE LastChange<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
-                 Cfg_TIME_TO_DELETE_IP_PREFS) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove old preferences");
+   DB_BuildQuery ("DELETE LOW_PRIORITY FROM IP_prefs"
+		  " WHERE LastChange<FROM_UNIXTIME(UNIX_TIMESTAMP()-'%lu')",
+                  Cfg_TIME_TO_DELETE_IP_PREFS);
+   DB_QueryDELETE_new ("can not remove old preferences");
   }
 
 /*****************************************************************************/
diff --git a/swad_profile.c b/swad_profile.c
index 2be7aaec9..23fe281f9 100644
--- a/swad_profile.c
+++ b/swad_profile.c
@@ -1057,13 +1057,9 @@ static void Prf_CreateUsrFigures (long UsrCod,const struct UsrFigures *UsrFigure
 
 void Prf_RemoveUsrFigures (long UsrCod)
   {
-   char *Query;
-
    /***** Remove user's figures *****/
-   if (asprintf (&Query,"DELETE FROM usr_figures WHERE UsrCod=%ld",
-	         UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not delete user's figures");
+   DB_BuildQuery ("DELETE FROM usr_figures WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not delete user's figures");
   }
 
 /*****************************************************************************/
diff --git a/swad_project.c b/swad_project.c
index 3af6d6821..91ef2d222 100644
--- a/swad_project.c
+++ b/swad_project.c
@@ -2116,7 +2116,6 @@ static void Prj_RemUsrFromPrj (Prj_RoleInProject_t RoleInProject)
    extern const char *Txt_THE_USER_X_has_been_removed_as_a_Y_from_the_project_Z;
    extern const char *Txt_PROJECT_ROLES_SINGUL_abc[Prj_NUM_ROLES_IN_PROJECT];
    extern const char *Txt_User_not_found_or_you_do_not_have_permission_;
-   char *Query;
    struct Project Prj;
    bool ItsMe;
 
@@ -2137,13 +2136,12 @@ static void Prj_RemUsrFromPrj (Prj_RoleInProject_t RoleInProject)
       if (Prj_CheckIfICanEditProject (Prj.PrjCod))
 	{
 	 /***** Remove user from the table of project-users *****/
-	 if (asprintf (&Query,"DELETE FROM prj_usr"
-			      " WHERE PrjCod=%ld AND RoleInProject=%u AND UsrCod=%ld",
-		       Prj.PrjCod,
-		       (unsigned) RoleInProject,
-		       Gbl.Usrs.Other.UsrDat.UsrCod) < 0)
-            Lay_NotEnoughMemoryExit ();
-	 DB_QueryDELETE_free (Query,"can not remove a user from a project");
+	 DB_BuildQuery ("DELETE FROM prj_usr"
+			" WHERE PrjCod=%ld AND RoleInProject=%u AND UsrCod=%ld",
+		        Prj.PrjCod,
+		        (unsigned) RoleInProject,
+		        Gbl.Usrs.Other.UsrDat.UsrCod);
+	 DB_QueryDELETE_new ("can not remove a user from a project");
 
 	 /***** Flush cache *****/
 	 ItsMe = Usr_ItsMe (Gbl.Usrs.Other.UsrDat.UsrCod);
@@ -2760,7 +2758,6 @@ void Prj_ReqRemProject (void)
 void Prj_RemoveProject (void)
   {
    extern const char *Txt_Project_X_removed;
-   char *Query;
    struct Project Prj;
    char PathRelPrj[PATH_MAX + 1];
 
@@ -2778,22 +2775,20 @@ void Prj_RemoveProject (void)
    if (Prj_CheckIfICanEditProject (Prj.PrjCod))
      {
       /***** Remove users in project *****/
-      if (asprintf (&Query,"DELETE FROM prj_usr USING projects,prj_usr"
-			   " WHERE projects.PrjCod=%ld AND projects.CrsCod=%ld"
-			   " AND projects.PrjCod=prj_usr.PrjCod",
-	            Prj.PrjCod,Gbl.CurrentCrs.Crs.CrsCod) < 0)
-         Lay_NotEnoughMemoryExit ();
-      DB_QueryDELETE_free (Query,"can not remove project");
+      DB_BuildQuery ("DELETE FROM prj_usr USING projects,prj_usr"
+		     " WHERE projects.PrjCod=%ld AND projects.CrsCod=%ld"
+		     " AND projects.PrjCod=prj_usr.PrjCod",
+	             Prj.PrjCod,Gbl.CurrentCrs.Crs.CrsCod);
+      DB_QueryDELETE_new ("can not remove project");
 
       /***** Flush cache *****/
       Prj_FlushCacheMyRoleInProject ();
 
       /***** Remove project *****/
-      if (asprintf (&Query,"DELETE FROM projects"
-			   " WHERE PrjCod=%ld AND CrsCod=%ld",
-	            Prj.PrjCod,Gbl.CurrentCrs.Crs.CrsCod) < 0)
-         Lay_NotEnoughMemoryExit ();
-      DB_QueryDELETE_free (Query,"can not remove project");
+      DB_BuildQuery ("DELETE FROM projects"
+		     " WHERE PrjCod=%ld AND CrsCod=%ld",
+	             Prj.PrjCod,Gbl.CurrentCrs.Crs.CrsCod);
+      DB_QueryDELETE_new ("can not remove project");
 
       /***** Remove information related to files in project *****/
       Brw_RemovePrjFilesFromDB (Prj.PrjCod);
@@ -3431,23 +3426,19 @@ static void Prj_UpdateProject (struct Project *Prj)
 
 void Prj_RemoveCrsProjects (long CrsCod)
   {
-   char *Query;
-
    /***** Remove users in projects of the course *****/
-   if (asprintf (&Query,"DELETE FROM prj_usr USING projects,prj_usr"
-			" WHERE projects.CrsCod=%ld"
-			" AND projects.PrjCod=prj_usr.PrjCod",
-                 CrsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove all the projects of a course");
+   DB_BuildQuery ("DELETE FROM prj_usr USING projects,prj_usr"
+		  " WHERE projects.CrsCod=%ld"
+		  " AND projects.PrjCod=prj_usr.PrjCod",
+                  CrsCod);
+   DB_QueryDELETE_new ("can not remove all the projects of a course");
 
    /***** Flush cache *****/
    Prj_FlushCacheMyRoleInProject ();
 
    /***** Remove projects *****/
-   if (asprintf (&Query,"DELETE FROM projects WHERE CrsCod=%ld",CrsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove all the projects of a course");
+   DB_BuildQuery ("DELETE FROM projects WHERE CrsCod=%ld",CrsCod);
+   DB_QueryDELETE_new ("can not remove all the projects of a course");
   }
 
 /*****************************************************************************/
@@ -3456,13 +3447,11 @@ void Prj_RemoveCrsProjects (long CrsCod)
 
 void Prj_RemoveUsrFromProjects (long UsrCod)
   {
-   char *Query;
    bool ItsMe;
 
    /***** Remove user from projects *****/
-   if (asprintf (&Query,"DELETE FROM prj_usr WHERE UsrCod=%ld",UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove user from projects");
+   DB_BuildQuery ("DELETE FROM prj_usr WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not remove user from projects");
 
    /***** Flush cache *****/
    ItsMe = Usr_ItsMe (UsrCod);
diff --git a/swad_record.c b/swad_record.c
index c1b85f914..4f0eba509 100644
--- a/swad_record.c
+++ b/swad_record.c
@@ -683,7 +683,6 @@ void Rec_AskConfirmRemFieldWithRecords (unsigned NumRecords)
 void Rec_RemoveFieldFromDB (void)
   {
    extern const char *Txt_Record_field_X_removed;
-   char *Query;
 
    /***** Get from the database the name of the field *****/
    Rec_GetFieldByCod (Gbl.CurrentCrs.Records.Field.FieldCod,
@@ -692,16 +691,14 @@ void Rec_RemoveFieldFromDB (void)
                       &Gbl.CurrentCrs.Records.Field.Visibility);
 
    /***** Remove field from all records *****/
-   if (asprintf (&Query,"DELETE FROM crs_records WHERE FieldCod=%ld",
-                 Gbl.CurrentCrs.Records.Field.FieldCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove field from all students' records");
+   DB_BuildQuery ("DELETE FROM crs_records WHERE FieldCod=%ld",
+                  Gbl.CurrentCrs.Records.Field.FieldCod);
+   DB_QueryDELETE_new ("can not remove field from all students' records");
 
    /***** Remove the field *****/
-   if (asprintf (&Query,"DELETE FROM crs_record_fields WHERE FieldCod=%ld",
-                 Gbl.CurrentCrs.Records.Field.FieldCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove field of record");
+   DB_BuildQuery ("DELETE FROM crs_record_fields WHERE FieldCod=%ld",
+                  Gbl.CurrentCrs.Records.Field.FieldCod);
+   DB_QueryDELETE_new ("can not remove field of record");
 
    /***** Write message to show the change made *****/
    snprintf (Gbl.Alert.Txt,sizeof (Gbl.Alert.Txt),
@@ -2032,15 +2029,12 @@ void Rec_UpdateCrsRecord (long UsrCod)
 
 void Rec_RemoveFieldsCrsRecordInCrs (long UsrCod,struct Course *Crs)
   {
-   char *Query;
-
    /***** Remove text of the field of record course *****/
-   if (asprintf (&Query,"DELETE FROM crs_records"
-			" WHERE UsrCod=%ld AND FieldCod IN"
-			" (SELECT FieldCod FROM crs_record_fields WHERE CrsCod=%ld)",
-                 UsrCod,Crs->CrsCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove user's record in a course");
+   DB_BuildQuery ("DELETE FROM crs_records"
+		  " WHERE UsrCod=%ld AND FieldCod IN"
+		  " (SELECT FieldCod FROM crs_record_fields WHERE CrsCod=%ld)",
+                  UsrCod,Crs->CrsCod);
+   DB_QueryDELETE_new ("can not remove user's record in a course");
   }
 
 /*****************************************************************************/
@@ -2049,12 +2043,9 @@ void Rec_RemoveFieldsCrsRecordInCrs (long UsrCod,struct Course *Crs)
 
 void Rec_RemoveFieldsCrsRecordAll (long UsrCod)
   {
-   char *Query;
-
    /***** Remove text of the field of record course *****/
-   if (asprintf (&Query,"DELETE FROM crs_records WHERE UsrCod=%ld",UsrCod) < 0)
-      Lay_NotEnoughMemoryExit ();
-   DB_QueryDELETE_free (Query,"can not remove user's records in all courses");
+   DB_BuildQuery ("DELETE FROM crs_records WHERE UsrCod=%ld",UsrCod);
+   DB_QueryDELETE_new ("can not remove user's records in all courses");
   }
 
 /*****************************************************************************/