Merge mysql.com:/home/ram/work/mysql-5.0-maint

into  mysql.com:/home/ram/work/b26851/b26851.5.0

mysql-test/r/strict.result

@@ -1391,4 +1391,10 @@ create table t1 (f1 set('a','a'));
 ERROR HY000: Column 'f1' has duplicated value 'a' in SET
 create table t1 (f1 enum('a','a'));
 ERROR HY000: Column 'f1' has duplicated value 'a' in ENUM
+set @@sql_mode='NO_ZERO_DATE';
+create table t1(a datetime not null);
+select count(*) from t1 where a is null;
+count(*)
+0
+drop table t1;
 End of 5.0 tests

mysql-test/t/strict.test

@@ -1258,4 +1258,12 @@ create table t1 (f1 set('a','a'));
 --error 1291
 create table t1 (f1 enum('a','a'));
 
+#
+# Bug #22824: strict, datetime, NULL, wrong warning
+#
+set @@sql_mode='NO_ZERO_DATE';
+create table t1(a datetime not null);
+select count(*) from t1 where a is null;
+drop table t1;
+
 --echo End of 5.0 tests

sql/item_cmpfunc.cc

@@ -316,7 +316,8 @@ static bool convert_constant_item(THD *thd, Field *field, Item **item)
   {
     /* For comparison purposes allow invalid dates like 2000-01-32 */
     ulong orig_sql_mode= thd->variables.sql_mode;
-    thd->variables.sql_mode|= MODE_INVALID_DATES;
+    thd->variables.sql_mode= (orig_sql_mode & ~MODE_NO_ZERO_DATE) | 
+                             MODE_INVALID_DATES;
     if (!(*item)->save_in_field(field, 1) && !((*item)->null_value))
     {
       Item *tmp=new Item_int_with_ref(field->val_int(), *item,