bk commit into 5.0 tree (ramil:1.2233) BUG#8143

[ramil]

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5.0 repository of ram. When ram does a push these changes will
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ChangeSet@stripped, 2006-07-23 15:25:30+05:00, ramil@stripped +3 -0
  Fix for bug #8143: A date with value 0 is treated as a NULL value

  mysql-test/r/delete.result@stripped, 2006-07-23 15:25:12+05:00, ramil@stripped +10 -0
    Fix for bug #8143: A date with value 0 is treated as a NULL value
      - test result

  mysql-test/t/delete.test@stripped, 2006-07-23 15:25:12+05:00, ramil@stripped +11 -0
    Fix for bug #8143: A date with value 0 is treated as a NULL value
      - test case

  sql/sql_delete.cc@stripped, 2006-07-23 15:25:12+05:00, ramil@stripped +8 -0
    Fix for bug #8143: A date with value 0 is treated as a NULL value
      - during SELECT queries processing we convert 'date[time]_field is null' 
        conditions into 'date[time]_field = 0000-00-00[ 00:00:00]' for not null 
        DATE and DATETIME fields. To be consistent, we have to do the same for DELETE
        queries. So we should call remove_eq_conds() in the mysql_delete() as well.
        Also it may simplify and speed up DELETE queries execution.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	ramil
# Host:	myoffice.izhnet.ru
# Root:	/usr/home/ram/work/5.0.b8143

--- 1.176/sql/sql_delete.cc	2006-07-23 15:26:06 +05:00
+++ 1.177/sql/sql_delete.cc	2006-07-23 15:26:06 +05:00
@@ -91,6 +91,14 @@
     /* Handler didn't support fast delete; Delete rows one by one */
   }
 
+  if (conds)
+  {
+    Item::cond_result result;
+    conds= remove_eq_conds(thd, conds, &result);
+    if (result == Item::COND_FALSE)             // Impossible where
+      limit= 0;
+  }
+
   table->used_keys.clear_all();
   table->quick_keys.clear_all();		// Can't use 'only index'
   select=make_select(table, 0, 0, conds, 0, &error);

--- 1.21/mysql-test/t/delete.test	2006-07-23 15:26:06 +05:00
+++ 1.22/mysql-test/t/delete.test	2006-07-23 15:26:06 +05:00
@@ -171,3 +171,14 @@
 # This should be empty
 select * from t3;
 drop table t1,t2,t3;
+
+#
+# Bug #8143: deleting '0000-00-00' values using IS NULL
+#
+
+create table t1(a date not null);
+insert into t1 values (0);
+select * from t1 where a is null;
+delete from t1 where a is null;
+select count(*) from t1;
+drop table t1;

--- 1.23/mysql-test/r/delete.result	2006-07-23 15:26:06 +05:00
+++ 1.24/mysql-test/r/delete.result	2006-07-23 15:26:06 +05:00
@@ -192,3 +192,13 @@
 select * from t3;
 a	b
 drop table t1,t2,t3;
+create table t1(a date not null);
+insert into t1 values (0);
+select * from t1 where a is null;
+a
+0000-00-00
+delete from t1 where a is null;
+select count(*) from t1;
+count(*)
+0
+drop table t1;