Item character set is stored in Item itself now, not in ITem->str_value

sql/item.cc

@@ -39,7 +39,8 @@ Item::Item():
 {
   marker= 0;
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
-  coercibility=COER_COERCIBLE;
+  collation= &my_charset_bin;
+  coercibility= COER_COERCIBLE;
   name= 0;
   decimals= 0; max_length= 0;
   THD *thd= current_thd;
@@ -67,6 +68,7 @@ Item::Item(THD *thd, Item &item):
   unsigned_flag(item.unsigned_flag),
   with_sum_func(item.with_sum_func),
   fixed(item.fixed),
+  collation(item.collation),
   coercibility(item.coercibility)
 {
   next=thd->free_list;			// Put in free list

sql/item.h

@@ -65,6 +65,7 @@ class Item {
   my_bool unsigned_flag;
   my_bool with_sum_func;
   my_bool fixed;                        /* If item fixed with fix_fields */
+  CHARSET_INFO  *collation;		/* character set && collation    */
   enum coercion coercibility;		/* Precedence order of collation */
 
   // alloc & destruct is done as start of select using sql_alloc
@@ -123,18 +124,17 @@ class Item {
   virtual Item *real_item() { return this; }
   virtual Item *get_tmp_table_item(THD *thd) { return copy_or_same(thd); }
 
-  virtual bool binary() const
-  { return str_value.charset()->state & MY_CS_BINSORT ? 1 : 0 ; }
   CHARSET_INFO *default_charset() const;
-  CHARSET_INFO *charset() const { return str_value.charset(); };
-  void set_charset(CHARSET_INFO *cs) { str_value.set_charset(cs); }
+  CHARSET_INFO *charset() const { return collation; };
+  void set_charset(CHARSET_INFO *cs) 
+  { collation= cs; }
   void set_charset(CHARSET_INFO *cs, enum coercion coer)
-  {
-    str_value.set_charset(cs);
-    coercibility= coer;
-  }
+  { collation= cs; coercibility= coer; }
   bool set_charset(CHARSET_INFO *cs1, enum coercion co1, 
   		   CHARSET_INFO *cs2, enum coercion co2);
+  bool binary() const
+  { return charset()->state & MY_CS_BINSORT ? 1 : 0 ; }
+  
   virtual void set_outer_resolving() {}
 
   // Row emulation
@@ -383,6 +383,7 @@ class Item_string :public Item
   Item_string(const char *str,uint length,
   	      CHARSET_INFO *cs, enum coercion coer= COER_COERCIBLE)
   {
+    set_charset(cs);
     str_value.set(str,length,cs);
     coercibility= coer;
     max_length=length;
@@ -392,6 +393,7 @@ class Item_string :public Item
   Item_string(const char *name_par, const char *str, uint length,
 	      CHARSET_INFO *cs, enum coercion coer= COER_COERCIBLE)
   {
+    set_charset(cs);
     str_value.set(str,length,cs);
     coercibility= coer;
     max_length=length;

sql/sql_select.cc

@@ -4142,10 +4142,10 @@ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
     case STRING_RESULT:
       if (item->max_length > 255)
 	new_field=  new Field_blob(item->max_length,maybe_null,
-				   item->name,table,item->str_value.charset());
+				   item->name,table,item->charset());
       else
 	new_field= new Field_string(item->max_length,maybe_null,
-				    item->name,table,item->str_value.charset());
+				    item->name,table,item->charset());
       break;
     case ROW_RESULT: 
     default: