Fixed bug in datetime range optimization

Docs/manual.texi

@@ -46771,8 +46771,6 @@ Our TODO section contains what we plan to have in 4.0. @xref{TODO MySQL 4.0}.
 
 @itemize @bullet
 @item
-Fixed bug in DROP DATABASE with symlink
-@item
 Multi-table @code{DELETE}.
 @item
 Don't support old client protocols prior to MySQL 3.21 any more.
@@ -46918,6 +46916,11 @@ not yet 100% confident in this code.
 @appendixsubsec Changes in release 3.23.51
 @itemize @bullet
 @item
+Fixed bug in @code{DROP DATABASE} with symlinked directory.
+@item
+Fixed optimization problem with @code{DATETIME} and value outside
+@code{DATETIME} range.
+@item
 Removed BDB documentation.
 @item
 Fixed mit-pthreads to compile with glibc 2.2 (needed for @code{make dist}).

mysql-test/r/type_datetime.result

@@ -33,3 +33,10 @@ date_format(a,"%Y-%m-%d")=b	right(a,6)=c+0	a=d+0
 1	1	1
 a
 0000-00-00 00:00:00
+date	numfacture	expedition
+0000-00-00 00:00:00	0	0001-00-00 00:00:00
+date	numfacture	expedition
+0000-00-00 00:00:00	0	0001-00-00 00:00:00
+0000-00-00 00:00:00	1212	0001-00-00 00:00:00
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t1	ref	expedition	expedition	8	const	1	where used

mysql-test/t/type_datetime.test

@@ -30,3 +30,23 @@ CREATE TABLE t1 (a datetime not null);
 insert into t1 values (0);
 select * from t1 where a is null;
 drop table t1;
+
+#
+# Test of datetime optimization
+#
+
+CREATE TABLE `t1` (
+  `date` datetime NOT NULL default '0000-00-00 00:00:00',
+  `numfacture` int(6) unsigned NOT NULL default '0',
+  `expedition` datetime NOT NULL default '0000-00-00 00:00:00',
+  PRIMARY KEY  (`numfacture`),
+  KEY `date` (`date`),
+  KEY `expedition` (`expedition`)
+) TYPE=MyISAM;
+
+INSERT INTO t1 (expedition) VALUES ('0001-00-00 00:00:00');
+SELECT * FROM t1 WHERE expedition='0001-00-00 00:00:00';
+INSERT INTO t1 (numfacture,expedition) VALUES ('1212','0001-00-00 00:00:00');
+SELECT * FROM t1 WHERE expedition='0001-00-00 00:00:00';
+EXPLAIN SELECT * FROM t1 WHERE expedition='0001-00-00 00:00:00';
+drop table t1;

sql/item.h

@@ -342,6 +342,25 @@ public:
 };
 
 
+/*
+  The following class is used to optimize comparing of date columns
+  We need to save the original item, to be able to set the field to the
+  original value in 'opt_range'.
+*/
+
+class Item_int_with_ref :public Item_int
+{
+  Item *ref;
+public:
+  Item_int_with_ref(longlong i, Item *ref_arg) :Item_int(i), ref(ref_arg)
+  {}
+  bool save_in_field(Field *field)
+  {
+    return ref->save_in_field(field);
+  }
+};
+
+
 #include "item_sum.h"
 #include "item_func.h"
 #include "item_cmpfunc.h"

sql/item_cmpfunc.cc

@@ -45,8 +45,8 @@ static bool convert_constant_item(Field *field, Item **item)
     (*item)->save_in_field(field);
     if (!((*item)->null_value))
     {
-      Item *tmp=new Item_int(field->val_int());
-      if ((tmp))
+      Item *tmp=new Item_int_with_ref(field->val_int(), *item);
+      if (tmp)
 	*item=tmp;
       return 1;
     }