assigned correct lex->current_select for derived tables (BUG#2349)

moved LIMIT initialialization, because it is need only for single select derived table

mysql-test/r/derived.result

@@ -245,3 +245,31 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
 3	UNION	t1	ALL	NULL	NULL	NULL	NULL	2	
 drop table t1;
+CREATE TABLE t1 (
+OBJECTID int(11) NOT NULL default '0',
+SORTORDER int(11) NOT NULL auto_increment,
+KEY t1_SortIndex (SORTORDER),
+KEY t1_IdIndex (OBJECTID)
+) TYPE=MyISAM DEFAULT CHARSET=latin1;
+Warnings:
+Warning	1286	'TYPE=database_engine' is deprecated. Use 'ENGINE=database_engine' instead.
+CREATE TABLE t2 (
+ID int(11) default NULL,
+PARID int(11) default NULL,
+UNIQUE KEY t2_ID_IDX (ID),
+KEY t2_PARID_IDX (PARID)
+) TYPE=MyISAM DEFAULT CHARSET=latin1;
+Warnings:
+Warning	1286	'TYPE=database_engine' is deprecated. Use 'ENGINE=database_engine' instead.
+INSERT INTO t2 VALUES (1000,0),(1001,0),(1002,0),(1003,0),(1008,1),(1009,1),(1010,1),(1011,1),(1016,2);
+CREATE TABLE t3 (
+ID int(11) default NULL,
+DATA decimal(10,2) default NULL,
+UNIQUE KEY t3_ID_IDX (ID)
+) TYPE=MyISAM DEFAULT CHARSET=latin1;
+Warnings:
+Warning	1286	'TYPE=database_engine' is deprecated. Use 'ENGINE=database_engine' instead.
+INSERT INTO t3 VALUES (1000,0.00),(1001,0.25),(1002,0.50),(1003,0.75),(1008,1.00),(1009,1.25),(1010,1.50),(1011,1.75);
+select 497, TMP.ID, NULL from (select 497 as ID, MAX(t3.DATA) as DATA      from t1 join t2 on (t1.ObjectID = t2.ID) join t3 on (t1.ObjectID = t3.ID) group by t2.ParID order by DATA DESC) as TMP;
+497	ID	NULL
+drop table t1, t2, t3;

mysql-test/t/derived.test

@@ -138,3 +138,29 @@ insert into t1 values (1),(2);
 select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
 explain select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
 drop table t1;
+
+
+#
+# correct lex->current_select
+#
+CREATE TABLE t1 (
+  OBJECTID int(11) NOT NULL default '0',
+  SORTORDER int(11) NOT NULL auto_increment,
+  KEY t1_SortIndex (SORTORDER),
+  KEY t1_IdIndex (OBJECTID)
+) TYPE=MyISAM DEFAULT CHARSET=latin1;
+CREATE TABLE t2 (
+  ID int(11) default NULL,
+  PARID int(11) default NULL,
+  UNIQUE KEY t2_ID_IDX (ID),
+  KEY t2_PARID_IDX (PARID)
+) TYPE=MyISAM DEFAULT CHARSET=latin1;
+INSERT INTO t2 VALUES (1000,0),(1001,0),(1002,0),(1003,0),(1008,1),(1009,1),(1010,1),(1011,1),(1016,2);
+CREATE TABLE t3 (
+  ID int(11) default NULL,
+  DATA decimal(10,2) default NULL,
+  UNIQUE KEY t3_ID_IDX (ID)
+) TYPE=MyISAM DEFAULT CHARSET=latin1;
+INSERT INTO t3 VALUES (1000,0.00),(1001,0.25),(1002,0.50),(1003,0.75),(1008,1.00),(1009,1.25),(1010,1.50),(1011,1.75);
+select 497, TMP.ID, NULL from (select 497 as ID, MAX(t3.DATA) as DATA      from t1 join t2 on (t1.ObjectID = t2.ID) join t3 on (t1.ObjectID = t3.ID) group by t2.ParID order by DATA DESC) as TMP;
+drop table t1, t2, t3;

sql/sql_derived.cc

@@ -146,17 +146,19 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
     }
     derived_result->set_table(table);
 
-    unit->offset_limit_cnt= first_select->offset_limit;
-    unit->select_limit_cnt= first_select->select_limit+
-      first_select->offset_limit;
-    if (unit->select_limit_cnt < first_select->select_limit)
-      unit->select_limit_cnt= HA_POS_ERROR;
-    if (unit->select_limit_cnt == HA_POS_ERROR)
-      first_select->options&= ~OPTION_FOUND_ROWS;
-
     if (is_union)
       res= mysql_union(thd, lex, derived_result, unit);
     else
+    {
+      unit->offset_limit_cnt= first_select->offset_limit;
+      unit->select_limit_cnt= first_select->select_limit+
+	first_select->offset_limit;
+      if (unit->select_limit_cnt < first_select->select_limit)
+	unit->select_limit_cnt= HA_POS_ERROR;
+      if (unit->select_limit_cnt == HA_POS_ERROR)
+	first_select->options&= ~OPTION_FOUND_ROWS;
+
+      lex->current_select= first_select;
       res= mysql_select(thd, &first_select->ref_pointer_array, 
 			(TABLE_LIST*) first_select->table_list.first,
 			first_select->with_wild,
@@ -169,6 +171,7 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
 			(first_select->options | thd->options |
 			 SELECT_NO_UNLOCK),
 			derived_result, unit, first_select);
+    }
 
     if (!res)
     {