merge with 5.3

sql/sql_insert.cc:
  CREATE ... IF NOT EXISTS may do nothing, but
  it is still not a failure. don't forget to my_ok it.
  ******
  CREATE ... IF NOT EXISTS may do nothing, but
  it is still not a failure. don't forget to my_ok it.
sql/sql_table.cc:
  small cleanup
  ******
  small cleanup

1 files changed, 10 insertions, 4 deletions

diff --git a/sql/item_buff.cc b/sql/item_buff.cc
index b0dbadcfda2..8c4224404d0 100644
--- a/sql/item_buff.cc
+++ b/sql/item_buff.cc
@@ -128,14 +128,20 @@ bool Cached_item_int::cmp(void)
 
 bool Cached_item_field::cmp(void)
 {
-  bool tmp= field->cmp(buff) != 0;		// This is not a blob!
-  if (tmp)
-    field->get_image(buff,length,field->charset());
+  bool tmp= FALSE;                              // Value is identical
+  /* Note that field can't be a blob here ! */
   if (null_value != field->is_null())
   {
     null_value= !null_value;
-    tmp=TRUE;
+    tmp= TRUE;                                  // Value has changed
   }
+
+  /*
+    If value is not null and value changed (from null to not null or
+    becasue of value change), then copy the new value to buffer.
+    */
+  if (! null_value && (tmp || (tmp= (field->cmp(buff) != 0))))
+    field->get_image(buff,length,field->charset());
   return tmp;
 }