1 files changed, 50 insertions, 30 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 66af96f671f..ab8acdd465f 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -145,7 +145,7 @@ void Item_func_not_all::print(String *str)
   1	Item was replaced with an integer version of the item
 */
 
-static bool convert_constant_item(Field *field, Item **item)
+static bool convert_constant_item(THD *thd, Field *field, Item **item)
 {
   if ((*item)->const_item())
   {
@@ -153,7 +153,7 @@ static bool convert_constant_item(Field *field, Item **item)
     {
       Item *tmp=new Item_int_with_ref(field->val_int(), *item);
       if (tmp)
-	*item=tmp;
+        thd->change_item_tree(item, tmp);
       return 1;					// Item was replaced
     }
   }
@@ -164,6 +164,7 @@ static bool convert_constant_item(Field *field, Item **item)
 void Item_bool_func2::fix_length_and_dec()
 {
   max_length= 1;				     // Function returns 0 or 1
+  THD *thd= current_thd;
 
   /*
     As some compare functions are generated after sql_yacc,
@@ -188,17 +189,26 @@ void Item_bool_func2::fix_length_and_dec()
   {
     uint strong= 0;
     uint weak= 0;
+    uint32 dummy_offset;
     DTCollation coll;
 
     if (args[0]->result_type() == STRING_RESULT &&
         args[1]->result_type() == STRING_RESULT &&
-        !my_charset_same(args[0]->collation.collation,
-                         args[1]->collation.collation) &&
+        String::needs_conversion(0, args[0]->collation.collation,
+                                    args[1]->collation.collation,
+                                    &dummy_offset) &&
         !coll.set(args[0]->collation, args[1]->collation, TRUE))
     {
       Item* conv= 0;
+      Item_arena *arena= thd->current_arena, backup;
       strong= coll.strong;
       weak= strong ? 0 : 1;
+      /*
+        In case we're in statement prepare, create conversion item
+        in its memory: it will be reused on each execute.
+      */
+      if (arena->is_stmt_prepare())
+          thd->set_n_backup_item_arena(arena, &backup);
       if (args[weak]->type() == STRING_ITEM)
       {
         String tmp, cstr;
@@ -211,26 +221,13 @@ void Item_bool_func2::fix_length_and_dec()
       }
       else
       {
-        THD *thd= current_thd;
-        /*
-          In case we're in prepared statement, create conversion
-          item in its memory: it will be reused on each execute.
-          (and don't juggle with mem_root's if it is ordinary statement).
-          We come here only during first fix_fields() because after creating
-          conversion item we will have arguments with compatible collations.
-        */
-        Item_arena *arena= thd->current_arena, backup;
-        if (arena->is_conventional())
-          arena= 0;
-        else
-          thd->set_n_backup_item_arena(arena, &backup);
 	conv= new Item_func_conv_charset(args[weak],
                                          args[strong]->collation.collation);
-        if (arena)
-          thd->restore_backup_item_arena(arena, &backup);
         conv->collation.set(args[weak]->collation.derivation);
         conv->fix_fields(thd, 0, &conv);
       }
+      if (arena->is_stmt_prepare())
+        thd->restore_backup_item_arena(arena, &backup);
       if (args[weak]->type() == FIELD_ITEM)
         ((Item_field *)args[weak])->no_const_subst= 1;
       args[weak]= conv ? conv : args[weak];
@@ -248,9 +245,9 @@ void Item_bool_func2::fix_length_and_dec()
   if (args[0]->type() == FIELD_ITEM)
   {
     Field *field=((Item_field*) args[0])->field;
-    if (field->store_for_compare())
+    if (field->can_be_compared_as_longlong())
     {
-      if (convert_constant_item(field,&args[1]))
+      if (convert_constant_item(thd, field,&args[1]))
       {
 	cmp.set_cmp_func(this, tmp_arg, tmp_arg+1,
 			 INT_RESULT);		// Works for all types.
@@ -261,9 +258,9 @@ void Item_bool_func2::fix_length_and_dec()
   if (args[1]->type() == FIELD_ITEM /* && !args[1]->const_item() */)
   {
     Field *field=((Item_field*) args[1])->field;
-    if (field->store_for_compare())
+    if (field->can_be_compared_as_longlong())
     {
-      if (convert_constant_item(field,&args[0]))
+      if (convert_constant_item(thd, field,&args[0]))
       {
 	cmp.set_cmp_func(this, tmp_arg, tmp_arg+1,
 			 INT_RESULT); // Works for all types.
@@ -841,6 +838,7 @@ longlong Item_func_interval::val_int()
 void Item_func_between::fix_length_and_dec()
 {
    max_length= 1;
+   THD *thd= current_thd;
 
   /*
     As some compare functions are generated after sql_yacc,
@@ -861,11 +859,15 @@ void Item_func_between::fix_length_and_dec()
   if (args[0]->type() == FIELD_ITEM)
   {
     Field *field=((Item_field*) args[0])->field;
-    if (field->store_for_compare())
+    if (field->can_be_compared_as_longlong())
     {
-      if (convert_constant_item(field,&args[1]))
+      /*
+        The following can't be recoded with || as convert_constant_item
+        changes the argument
+      */
+      if (convert_constant_item(thd, field,&args[1]))
 	cmp_type=INT_RESULT;			// Works for all types.
-      if (convert_constant_item(field,&args[2]))
+      if (convert_constant_item(thd, field,&args[2]))
 	cmp_type=INT_RESULT;			// Works for all types.
     }
   }
@@ -1167,6 +1169,15 @@ Item_func_nullif::val_str(String *str)
   return res;
 }
 
+
+bool
+Item_func_nullif::is_null()
+{
+  if (!cmp.compare())
+    return (null_value=1);
+  return 0;
+}
+
 /*
   CASE expression 
   Return the matching ITEM or NULL if all compares (including else) failed
@@ -1751,6 +1762,7 @@ void Item_func_in::fix_length_and_dec()
 {
   Item **arg, **arg_end;
   uint const_itm= 1;
+  THD *thd= current_thd;
   
   agg_cmp_type(&cmp_type, args, arg_count);
 
@@ -1788,6 +1800,9 @@ void Item_func_in::fix_length_and_dec()
          Conversion is possible:
          All IN arguments are constants.
       */
+      Item_arena *arena= thd->current_arena, backup;
+      if (arena->is_stmt_prepare())
+        thd->set_n_backup_item_arena(arena, &backup);
       for (arg= args+1, arg_end= args+arg_count; arg < arg_end; arg++)
       {
         if (!my_charset_same(cmp_collation.collation,
@@ -1803,6 +1818,8 @@ void Item_func_in::fix_length_and_dec()
           arg[0]= conv;
         }
       }
+      if (arena->is_stmt_prepare())
+        thd->restore_backup_item_arena(arena, &backup);
     }
   }
   
@@ -1830,7 +1847,7 @@ void Item_func_in::fix_length_and_dec()
       DBUG_ASSERT(0);
       return;
     }
-    if (array && !(current_thd->is_fatal_error))	// If not EOM
+    if (array && !(thd->is_fatal_error))		// If not EOM
     {
       uint j=0;
       for (uint i=1 ; i < arg_count ; i++)
@@ -2048,7 +2065,8 @@ Item *Item_cond::transform(Item_transformer transformer, byte *arg)
 }
 
 
-void Item_cond::split_sum_func(Item **ref_pointer_array, List<Item> &fields)
+void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
+                               List<Item> &fields)
 {
   List_iterator<Item> li(list);
   Item *item;
@@ -2057,13 +2075,15 @@ void Item_cond::split_sum_func(Item **ref_pointer_array, List<Item> &fields)
   while ((item=li++))
   {
     if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
-      item->split_sum_func(ref_pointer_array, fields);
+      item->split_sum_func(thd, ref_pointer_array, fields);
     else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
     {
+      Item **ref= li.ref();
       uint el= fields.elements;
+      Item *new_item= new Item_ref(ref_pointer_array + el, 0, item->name);
       fields.push_front(item);
       ref_pointer_array[el]= item;
-      li.replace(new Item_ref(ref_pointer_array + el, li.ref(), 0, item->name));
+      thd->change_item_tree(ref, new_item);
     }
     item->update_used_tables();
     used_tables_cache|=item->used_tables();