diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result
index 2618741a520..b5b944583da 100644
--- a/mysql-test/r/subselect.result
+++ b/mysql-test/r/subselect.result
@@ -159,6 +159,23 @@ UNIQUE KEY `email` (`email`)
 INSERT INTO inscrit (pseudo,email) VALUES ('joce','test');
 INSERT INTO inscrit (pseudo,email) VALUES ('joce1','test1');
 INSERT INTO inscrit (pseudo,email) VALUES ('2joce1','2test1');
+EXPLAIN SELECT pseudo,(SELECT email FROM inscrit WHERE pseudo=(SELECT
+pseudo FROM inscrit WHERE pseudo='joce')) FROM inscrit WHERE pseudo=(SELECT
+pseudo FROM inscrit WHERE pseudo='joce');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	inscrit	const	PRIMARY	PRIMARY	35	const	1	
+4	SUBSELECT	inscrit	const	PRIMARY	PRIMARY	35	const	1	
+2	SUBSELECT	inscrit	const	PRIMARY	PRIMARY	35	const	1	
+3	SUBSELECT	inscrit	const	PRIMARY	PRIMARY	35	const	1	
+SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo,email FROM
+inscrit WHERE pseudo='joce');
+Subselect returns more than 1 field
+SELECT pseudo FROM inscrit WHERE pseudo=(SELECT * FROM inscrit WHERE
+pseudo='joce');
+Subselect returns more than 1 field
+SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo FROM inscrit WHERE pseudo='joce');
+pseudo
+joce
 SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo FROM inscrit WHERE pseudo LIKE '%joce%');
 Subselect returns more than 1 record
 drop table if exists t1,t2,t3,t4,t5,attend,clinic,inscrit;
diff --git a/mysql-test/t/subselect.test b/mysql-test/t/subselect.test
index c34332d6d90..120cbcbc05f 100644
--- a/mysql-test/t/subselect.test
+++ b/mysql-test/t/subselect.test
@@ -82,6 +82,16 @@ CREATE TABLE `inscrit` (
 INSERT INTO inscrit (pseudo,email) VALUES ('joce','test');
 INSERT INTO inscrit (pseudo,email) VALUES ('joce1','test1');
 INSERT INTO inscrit (pseudo,email) VALUES ('2joce1','2test1');
+EXPLAIN SELECT pseudo,(SELECT email FROM inscrit WHERE pseudo=(SELECT
+pseudo FROM inscrit WHERE pseudo='joce')) FROM inscrit WHERE pseudo=(SELECT
+pseudo FROM inscrit WHERE pseudo='joce');
+-- error 1239
+SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo,email FROM
+inscrit WHERE pseudo='joce');
+-- error 1239
+SELECT pseudo FROM inscrit WHERE pseudo=(SELECT * FROM inscrit WHERE
+pseudo='joce');
+SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo FROM inscrit WHERE pseudo='joce');
 -- error 1240
 SELECT pseudo FROM inscrit WHERE pseudo=(SELECT pseudo FROM inscrit WHERE pseudo LIKE '%joce%');
 
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 2d08b9cb6b5..de9c7e11313 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -81,15 +81,17 @@ void Item_subselect::make_field (Send_field *tmp_field)
 
 bool Item_subselect::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
 {
-  // Is it one field subselect?
-  if (engine->cols() > max_columns)
-  {  
-    my_message(ER_SUBSELECT_NO_1_COL, ER(ER_SUBSELECT_NO_1_COL), MYF(0));
-    return 1;
-  }
   int res= engine->prepare();
   if (!res)
+  {
+    // Is it one field subselect?
+    if (engine->cols() > max_columns)
+    {  
+      my_message(ER_SUBSELECT_NO_1_COL, ER(ER_SUBSELECT_NO_1_COL), MYF(0));
+      return 1;
+    }
     fix_length_and_dec();
+  }
   return res;
 }
 
@@ -150,6 +152,8 @@ String *Item_singleval_subselect::val_str (String *str)
     assign_null();
     return 0;
   }
+  // Assign temporary buffer with stored value
+  str_value.set(string_value, 0, string_value.length());
   return &str_value;
 }
 
@@ -208,7 +212,7 @@ subselect_single_select_engine::subselect_single_select_engine(THD *thd,
 							       select_subselect *result,
 							       Item_subselect *item):
   subselect_engine(thd, item, result),
-   executed(0), optimized(0)
+    prepared(0), optimized(0), executed(0)
 {
   select_lex= select;
   SELECT_LEX_UNIT *unit= select_lex->master_unit();
@@ -247,6 +251,9 @@ subselect_union_engine::subselect_union_engine(THD *thd,
 
 int subselect_single_select_engine::prepare()
 {
+  if (prepared)
+    return 0;
+  prepared= 1;
   SELECT_LEX *save_select= thd->lex.select;
   thd->lex.select= select_lex;
   if(join->prepare((TABLE_LIST*) select_lex->table_list.first,
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 5d070871b49..33f82982708 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -80,10 +80,16 @@ public:
 class Item_singleval_subselect :public Item_subselect
 {
 protected:
-  longlong int_value; /* here stored integer value of this item */
-  double real_value; /* here stored real value of this item */
+  longlong int_value; /* Here stored integer value of this item */
+  double real_value; /* Here stored real value of this item */
+  /* 
+     Here stored string value of this item.
+     (str_value used only as temporary buffer, because it can be changed 
+     by Item::save_field)
+  */
+  String string_value; 
   enum Item_result res_type; /* type of results */
-
+  
 public:
   Item_singleval_subselect(THD *thd, st_select_lex *select_lex);
   Item_singleval_subselect(Item_singleval_subselect *item):
@@ -91,6 +97,7 @@ public:
   {
     int_value= item->int_value;
     real_value= item->real_value;
+    string_value.set(item->string_value, 0, item->string_value.length());
     max_length= item->max_length;
     decimals= item->decimals;
     res_type= item->res_type;
@@ -172,8 +179,9 @@ public:
 
 class subselect_single_select_engine: public subselect_engine
 {
-  my_bool executed; /* simple subselect is executed */
+  my_bool prepared; /* simple subselect is prepared */
   my_bool optimized; /* simple subselect is optimized */
+  my_bool executed; /* simple subselect is executed */
   st_select_lex *select_lex; /* corresponding select_lex */
   JOIN * join; /* corresponding JOIN structure */
 public:
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 648e05c1610..f778a721f54 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -884,9 +884,14 @@ bool select_singleval_subselect::send_data(List<Item> &items)
     it->decimals= val_item->decimals;
     it->binary= val_item->binary;
     it->int_value= val_item->val_int();
-    String *s= val_item->val_str(&it->str_value);
-    if (s != &it->str_value)
-      it->str_value.set(*s, 0, s->length());
+    String *s= val_item->val_str(&it->string_value);
+    if (s != &it->string_value)
+    {
+      it->string_value.set(*s, 0, s->length());
+    }
+    // TODO: remove when correct charset handling appeared for Item
+    it->str_value.set(*s, 0, s->length()); // store charset
+
     it->res_type= val_item->result_type();
   }
   it->assigned(1);
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 122ceeedc54..46206079084 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -944,7 +944,7 @@ void st_select_lex_unit::init_query()
   global_parameters= this;
   select_limit_cnt= HA_POS_ERROR;
   offset_limit_cnt= 0;
-  optimized= 0;
+  prepared= optimized= 0;
   item= 0;
 }
 
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index acf73f34d5d..fe708d3b782 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -227,6 +227,7 @@ protected:
   select_result *result;
   int res;
   bool describe, found_rows_for_union,
+    prepared, //prepare phase already performed for UNION (unit)
     optimized; // optimize phase already performed for UNION (unit)
 public:
   /*
diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 1a18759eb5b..74cb8f6ffea 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -104,11 +104,16 @@ bool select_union::flush()
 typedef JOIN * JOIN_P;
 int st_select_lex_unit::prepare(THD *thd, select_result *result)
 {
+  DBUG_ENTER("st_select_lex_unit::prepare");
+
+  if (prepared)
+    DBUG_RETURN(0);
+  prepared= 1;
+    
   describe=(first_select()->options & SELECT_DESCRIBE) ? 1 : 0;
   res= 0;
   found_rows_for_union= false;
   TMP_TABLE_PARAM tmp_table_param;
-  DBUG_ENTER("st_select_lex_unit::prepare");
   this->thd= thd;
   this->result= result;
   SELECT_LEX *lex_select_save= thd->lex.select;