Fixed LP bug #825035.

The value of maybe_null flag should be saved for the second execution
of a prepared statement from SELECT that uses an outer join.

mysql-test/r/join_outer.result

@@ -1593,3 +1593,25 @@ FROM t1 LEFT JOIN t2 ON (t2.b) IN (SELECT c2 from t3) AND t2.a = 1;
 b
 NULL
 DROP TABLE t1,t2,t3;
+#
+# LP bug #825035: second execution of PS with outer join
+#
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1),(2),(3),(4);
+CREATE TABLE t2 (a int);
+PREPARE stmt FROM 
+"SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a";
+EXECUTE stmt;
+a	a
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+EXECUTE stmt;
+a	a
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1,t2;

mysql-test/r/join_outer_jcl6.result

@@ -1602,6 +1602,28 @@ FROM t1 LEFT JOIN t2 ON (t2.b) IN (SELECT c2 from t3) AND t2.a = 1;
 b
 NULL
 DROP TABLE t1,t2,t3;
+#
+# LP bug #825035: second execution of PS with outer join
+#
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1),(2),(3),(4);
+CREATE TABLE t2 (a int);
+PREPARE stmt FROM 
+"SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a";
+EXECUTE stmt;
+a	a
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+EXECUTE stmt;
+a	a
+1	NULL
+2	NULL
+3	NULL
+4	NULL
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1,t2;
 set join_cache_level=default;
 show variables like 'join_cache_level';
 Variable_name	Value

mysql-test/t/join_outer.test

@@ -1154,3 +1154,22 @@ SELECT t2.b
 FROM t1 LEFT JOIN t2 ON (t2.b) IN (SELECT c2 from t3) AND t2.a = 1;
 
 DROP TABLE t1,t2,t3;
+
+--echo #
+--echo # LP bug #825035: second execution of PS with outer join
+--echo #
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1),(2),(3),(4);
+
+CREATE TABLE t2 (a int);
+
+PREPARE stmt FROM 
+"SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a";
+
+EXECUTE stmt;
+EXECUTE stmt;
+
+DEALLOCATE PREPARE stmt;
+
+DROP TABLE t1,t2;

sql/sql_base.cc

@@ -7847,6 +7847,7 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
       {
         table_list->table->tablenr= table_list->tablenr_exec;
         table_list->table->map= table_list->map_exec;
+        table_list->table->maybe_null= table_list->maybe_null_exec;
         table_list->table->pos_in_table_list= table_list;
       }
       select_lex->leaf_tables.push_back(table_list);

sql/sql_insert.cc

@@ -3015,6 +3015,7 @@ bool mysql_insert_select_prepare(THD *thd)
       select_lex->leaf_tables_exec.push_back(table);
       table->tablenr_exec= table->table->tablenr;
       table->map_exec= table->table->map;
+      table->maybe_null_exec= table->table->maybe_null;
     }
     if (arena)
       thd->restore_active_arena(arena, &backup);

sql/sql_lex.cc

@@ -3588,6 +3588,10 @@ bool st_select_lex::save_leaf_tables(THD *thd)
       return 1;
     table->tablenr_exec= table->table->tablenr;
     table->map_exec= table->table->map;
+    if (join && (join->select_options & SELECT_DESCRIBE))
+      table->maybe_null_exec= 0;
+    else
+      table->maybe_null_exec= table->table->maybe_null;
   }
   if (arena)
     thd->restore_active_arena(arena, &backup);

sql/sql_union.cc

@@ -371,6 +371,7 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
     ulonglong create_options;
     uint save_tablenr= 0;
     table_map save_map= 0;
+    uint save_maybe_null= 0;
 
     while ((type= tp++))
     {
@@ -429,6 +430,7 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
     {
       save_tablenr= result_table_list.tablenr_exec;
       save_map= result_table_list.map_exec;
+      save_maybe_null= result_table_list.maybe_null_exec;
     }
     bzero((char*) &result_table_list, sizeof(result_table_list));
     result_table_list.db= (char*) "";
@@ -438,6 +440,7 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
     {
       result_table_list.tablenr_exec= save_tablenr;
       result_table_list.map_exec= save_map;
+      result_table_list.maybe_null_exec= save_maybe_null;
     }
 
     thd_arg->lex->current_select= lex_select_save;

sql/table.h

@@ -1448,6 +1448,7 @@ struct TABLE_LIST
   table_map     map_exec;
   /* TODO: check if this can be joined with jtbm_table_no */
   uint          tablenr_exec;
+  uint          maybe_null_exec;
 
   /* Ptr to parent MERGE table list item. See top comment in ha_myisammrg.cc */
   TABLE_LIST    *parent_l;