Manually merged

client/mysqltest.c:
  Auto merged
myisam/mi_check.c:
  Auto merged
mysql-test/r/update.result:
  Auto merged
mysql-test/t/update.test:
  Auto merged
sql/item_timefunc.h:
  Auto merged
sql/spatial.cc:
  Auto merged
sql/sql_select.h:
  Auto merged
BitKeeper/deleted/.del-acinclude.m4~f4ab416bac5003:
  Auto merged

1 files changed, 12 insertions, 3 deletions

diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index f83bd24f5d3..10debc9427d 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -132,7 +132,7 @@ int mysql_update(THD *thd,
   ha_rows	updated, found;
   key_map	old_used_keys;
   TABLE		*table;
-  SQL_SELECT	*select;
+  SQL_SELECT	*select= 0;
   READ_RECORD	info;
   SELECT_LEX    *select_lex= &thd->lex->select_lex;
   bool need_reopen;
@@ -228,11 +228,20 @@ int mysql_update(THD *thd,
     DBUG_RETURN(1);				/* purecov: inspected */
   }
 
+  if (conds)
+  {
+    Item::cond_result cond_value;
+    conds= remove_eq_conds(thd, conds, &cond_value);
+    if (cond_value == Item::COND_FALSE)
+      limit= 0;                                   // Impossible WHERE
+  }
   // Don't count on usage of 'only index' when calculating which key to use
   table->used_keys.clear_all();
   select= make_select(table, 0, 0, conds, 0, &error);
-  if (error ||
-      (select && select->check_quick(thd, safe_update, limit)) || !limit)
+  if (limit)
+    select=make_select(table,0,0,conds,&error);
+  if (error || !limit ||
+      (select && select->check_quick(thd, safe_update, limit)))
   {
     delete select;
     free_underlaid_joins(thd, select_lex);