From 3f0f275030246c333b38c48c8b8be204e95c4f38 Mon Sep 17 00:00:00 2001
From: "tnurnberg@mysql.com/white.intern.koehntopp.de" <>
Date: Tue, 11 Dec 2007 10:12:05 +0100
Subject: Bug#31990: MINUTE() and SECOND() return bogus results when used on a
 DATE

HOUR(), MINUTE(), ... returned spurious results when used on a DATE-cast.
This happened because DATE-cast object did not overload get_time() method
in superclass Item. The default method was inappropriate here and
misinterpreted the data.

Patch adds missing method; get_time() on DATE-casts now returns SQL-NULL
on NULL input, 0 otherwise. This coincides with the way DATE-columns
behave.

Also fixes similar bug in Date-Field now.
---
 sql/field.cc         | 7 +++++++
 sql/field.h          | 1 +
 sql/item_timefunc.cc | 7 +++++++
 sql/item_timefunc.h  | 1 +
 4 files changed, 16 insertions(+)

(limited to 'sql')

diff --git a/sql/field.cc b/sql/field.cc
index 86853389c64..db438c7c4d0 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -5194,6 +5194,13 @@ String *Field_date::val_str(String *val_buffer,
 }
 
 
+bool Field_date::get_time(MYSQL_TIME *ltime)
+{
+  bzero((char *)ltime, sizeof(MYSQL_TIME));
+  return 0;
+}
+
+
 int Field_date::cmp(const char *a_ptr, const char *b_ptr)
 {
   int32 a,b;
diff --git a/sql/field.h b/sql/field.h
index 8c01931fa21..8ae39f78558 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -933,6 +933,7 @@ public:
   double val_real(void);
   longlong val_int(void);
   String *val_str(String*,String *);
+  bool get_time(MYSQL_TIME *ltime);
   bool send_binary(Protocol *protocol);
   int cmp(const char *,const char*);
   void sort_string(char *buff,uint length);
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index c1fa9dce038..7ed5e375f5b 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -2645,6 +2645,13 @@ bool Item_date_typecast::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
 }
 
 
+bool Item_date_typecast::get_time(MYSQL_TIME *ltime)
+{
+  bzero((char *)ltime, sizeof(MYSQL_TIME));
+  return args[0]->null_value;
+}
+
+
 String *Item_date_typecast::val_str(String *str)
 {
   DBUG_ASSERT(fixed == 1);
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index a5ecbc57e8d..b647e93b700 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -779,6 +779,7 @@ public:
   const char *func_name() const { return "cast_as_date"; }
   String *val_str(String *str);
   bool get_date(MYSQL_TIME *ltime, uint fuzzy_date);
+  bool get_time(MYSQL_TIME *ltime);
   const char *cast_type() const { return "date"; }
   enum_field_types field_type() const { return MYSQL_TYPE_DATE; }
   Field *tmp_table_field(TABLE *t_arg)
-- 
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