Backport of fix to bug #33629 into mysql-next-mr-bugfixing.

Gleb Shchepa · Gleb Shchepa · commit 9dc1353d5ca2 · 2009-10-13T21:50:08.000+05:00
Bug #33629: last_day function can return null, but has 'not null' flag set for result

LAST_DAY and MAKEDATE functions are documented as
returning NULL value, but actually they was implemented
as returning NOT NULL typed values.

That caused a confusing error "ERROR 1048 (23000): Column
'...' cannot be null" on queries like: 

  SELECT 1 FROM (SELECT LAST_DAY('0')) a;

--BZR--
revision-id: gshchepa@mysql.com-20091013165008-ay8db1u1u8q4daz5
property-branch-nick: mysql-next-mr-bugfixing
property-file-info: ld7:file_id70:sp1f-func_sapdb.result-20030623075631-kd3o45rwsfzikxjuk7r2deumuhaphbn77:message36:  Updated test case for bug #33629.
property-file-info: 4:path30:mysql-test/r/func_sapdb.resulted7:file_id69:sp1f-func_time.result-20001228015633-voo54ouzgwctcbmk22zwazoev5os5o4x7:message36:  Updated test case for bug #33629.
property-file-info: 4:path29:mysql-test/r/func_time.resulted7:file_id69:sp1f-type_date.result-20001228015634-drbo6443s5wzxlf3enjz3qt43ttjf6ik7:message34:  Added test case for bug #33629.
property-file-info: 4:path29:mysql-test/r/type_date.resulted7:file_id67:sp1f-type_date.test-20001228015637-6hhkz7fj6xpjxak4s3sq7ohgddycrhvz7:message34:  Added test case for bug #33629.
property-file-info: 4:path27:mysql-test/t/type_date.tested7:file_id68:sp1f-item_timefunc.h-19700101030959-o34ypz6ggolzqmhgsjnqh6inkvgugi467:message338:  Bug #33629: last_day function can return null, but has 'not null' flag set for result
property-file-info:   
property-file-info:   1. The Item_func_makedate::fix_length_and_dec method
property-file-info:      has been modified to declare MAKEDATE() as a function
property-file-info:      returning nullable value.
property-file-info:   2. The Item_func_last_day::fix_length_and_dec method
property-file-info:      has been overloaded for the same purpose.
property-file-info: 4:path19:sql/item_timefunc.hee
testament3-sha1: 00121556ee1f79e071021de9bac326477a1f7392
diff --git a/mysql-test/r/func_sapdb.result b/mysql-test/r/func_sapdb.result
@@ -194,7 +194,7 @@ date("1997-12-31 23:59:59.000001") as f8,
 time("1997-12-31 23:59:59.000001") as f9;
 describe t1;
 Field	Type	Null	Key	Default	Extra
-f1	date	NO		0000-00-00	
+f1	date	YES		NULL	
 f2	datetime	YES		NULL	
 f3	time	YES		NULL	
 f4	time	YES		NULL	
diff --git a/mysql-test/r/func_time.result b/mysql-test/r/func_time.result
@@ -814,7 +814,7 @@ create table t1 select last_day('2000-02-05') as a,
 from_days(to_days("960101")) as b;
 describe t1;
 Field	Type	Null	Key	Default	Extra
-a	date	NO		0000-00-00	
+a	date	YES		NULL	
 b	date	YES		NULL	
 select * from t1;
 a	b
diff --git a/mysql-test/r/type_date.result b/mysql-test/r/type_date.result
@@ -276,3 +276,25 @@ a
 0000-00-01
 drop table t1;
 End of 5.1 tests
+#
+# Bug #33629: last_day function can return null, but has 'not null'
+#             flag set for result
+#
+SELECT 1 FROM (SELECT LAST_DAY('0')) a;
+1
+1
+Warnings:
+Warning	1292	Incorrect datetime value: '0'
+SELECT 1 FROM (SELECT MAKEDATE(2011,0)) a;
+1
+1
+CREATE TABLE t1 AS
+SELECT LAST_DAY('1970-01-01') AS f1,
+MAKEDATE(1970, 1)      AS f2;
+DESCRIBE t1;
+Field	Type	Null	Key	Default	Extra
+f1	date	YES		NULL	
+f2	date	YES		NULL	
+DROP TABLE t1;
+#
+End of 6.0 tests
diff --git a/mysql-test/t/type_date.test b/mysql-test/t/type_date.test
@@ -247,3 +247,21 @@ select * from t1 where a between '0000-00-01' and '0000-00-02';
 drop table t1;
 
 --echo End of 5.1 tests
+
+--echo #
+--echo # Bug #33629: last_day function can return null, but has 'not null'
+--echo #             flag set for result
+--echo #
+
+SELECT 1 FROM (SELECT LAST_DAY('0')) a;
+SELECT 1 FROM (SELECT MAKEDATE(2011,0)) a;
+
+CREATE TABLE t1 AS
+  SELECT LAST_DAY('1970-01-01') AS f1,
+         MAKEDATE(1970, 1)      AS f2;
+DESCRIBE t1;
+DROP TABLE t1;
+
+--echo #
+
+--echo End of 6.0 tests
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
@@ -871,6 +871,7 @@ class Item_func_makedate :public Item_date_func
   { 
     decimals=0;
     max_length=MAX_DATE_WIDTH*MY_CHARSET_BIN_MB_MAXLEN;
+    maybe_null= 1;
   }
   longlong val_int();
 };
@@ -1025,4 +1026,9 @@ class Item_func_last_day :public Item_date
   Item_func_last_day(Item *a) :Item_date(a) {}
   const char *func_name() const { return "last_day"; }
   bool get_date(MYSQL_TIME *res, uint fuzzy_date);
+  void fix_length_and_dec()
+  { 
+    Item_date::fix_length_and_dec();
+    maybe_null= 1;
+  }
 };
