TEMPORARY MERGE tables are allowed

mysql-test/r/merge.result

@@ -130,3 +130,9 @@ a
 a	b
 1	1
 1	2
+a
+1
+2
+a
+1
+2

mysql-test/t/merge.test

@@ -114,3 +114,22 @@ insert into t2 values (1,1),(2,2),(0,0),(4,4),(5,5),(6,6);
 flush tables;
 select * from t3 where a=1 order by b limit 2;
 drop table t3,t1,t2;
+
+#
+# temporary merge tables
+#
+drop table if exists t1, t2, t3, t4, t5, t6;
+create table t1 (a int not null);
+create table t2 (a int not null);
+insert into t1 values (1);
+insert into t2 values (2);
+create temporary table t3 (a int not null) TYPE=MERGE UNION=(t1,t2);
+select * from t3;
+create temporary table t4 (a int not null);
+create temporary table t5 (a int not null);
+insert into t4 values (1);
+insert into t5 values (2);
+create temporary table t6 (a int not null) TYPE=MERGE UNION=(t4,t5);
+select * from t6;
+drop table if exists t1, t2, t3, t4, t5, t6;
+

sql/ha_myisammrg.cc

@@ -264,7 +264,28 @@ int ha_myisammrg::create(const char *name, register TABLE *form,
 					sizeof(char*))))
     DBUG_RETURN(1);
   for (pos=table_names ; tables ; tables=tables->next)
-    *pos++= tables->real_name;
+  {
+    char *table_name;
+    if (create_info->options & HA_LEX_CREATE_TMP_TABLE)
+    {
+      TABLE **tbl=find_temporary_table(current_thd,
+          tables->db, tables->real_name);
+      if (!tbl)
+      {
+        table_name=sql_alloc(1+
+            my_snprintf(buff,FN_REFLEN,"%s/%s/%s",mysql_real_data_home,
+                        tables->db, tables->real_name));
+        if (!table_name)
+          DBUG_RETURN(1);
+        strcpy(table_name, buff);
+      }
+      else
+        table_name=(*tbl)->path;
+    }
+    else
+      table_name=tables->real_name;
+    *pos++= table_name;
+  }
   *pos=0;
   DBUG_RETURN(myrg_create(fn_format(buff,name,"","",2+4+16),
 			  (const char **) table_names, (my_bool) 0));