From f467f4bb934a9a73e9a5643f5b674d02d4d0aa6b Mon Sep 17 00:00:00 2001
From: Alexander Barkov <bar@mnogosearch.org>
Date: Mon, 28 Apr 2014 17:01:58 +0400
Subject: [PATCH] MDEV-5459 Illegal mix of collations for datetime

---
 mysql-test/r/ctype_cp1251.result | 10 ++++++++++
 mysql-test/t/ctype_cp1251.test   |  8 ++++++++
 sql/item_cmpfunc.cc              |  4 ++--
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/mysql-test/r/ctype_cp1251.result b/mysql-test/r/ctype_cp1251.result
index 9c7164911af..313f60ef276 100644
--- a/mysql-test/r/ctype_cp1251.result
+++ b/mysql-test/r/ctype_cp1251.result
@@ -3282,5 +3282,15 @@ SELECT COALESCE(IF(test1=1, NULL, 1), test2) FROM t1;
 COALESCE(IF(test1=1, NULL, 1), test2)
 DROP TABLE t1;
 #
+# MDEV-5459 Illegal mix of collations for datetime
+#
+SET NAMES cp1251;
+CREATE TABLE t1 (dt DATETIME);
+INSERT INTO t1 VALUES ('2014-01-02 10:20:30');
+SELECT date(dt) FROM t1 WHERE (CASE WHEN 1 THEN date(dt) ELSE null END >= '2013-12-01 00:00:00');
+date(dt)
+2014-01-02
+DROP TABLE t1;
+#
 # End of 5.5 tests
 #
diff --git a/mysql-test/t/ctype_cp1251.test b/mysql-test/t/ctype_cp1251.test
index ab260f0c7e8..0455f579922 100644
--- a/mysql-test/t/ctype_cp1251.test
+++ b/mysql-test/t/ctype_cp1251.test
@@ -95,6 +95,14 @@ SELECT COALESCE(IF(test1=1, 1, NULL), test2) FROM t1;
 SELECT COALESCE(IF(test1=1, NULL, 1), test2) FROM t1;
 DROP TABLE t1;
 
+--echo #
+--echo # MDEV-5459 Illegal mix of collations for datetime
+--echo #
+SET NAMES cp1251;
+CREATE TABLE t1 (dt DATETIME);
+INSERT INTO t1 VALUES ('2014-01-02 10:20:30');
+SELECT date(dt) FROM t1 WHERE (CASE WHEN 1 THEN date(dt) ELSE null END >= '2013-12-01 00:00:00');
+DROP TABLE t1;
 
 --echo #
 --echo # End of 5.5 tests
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index fa14f7bdcf1..998cb1cbd64 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -549,8 +549,8 @@ void Item_bool_func2::fix_length_and_dec()
   */
 
   DTCollation coll;
-  if (args[0]->result_type() == STRING_RESULT &&
-      args[1]->result_type() == STRING_RESULT &&
+  if (args[0]->cmp_type() == STRING_RESULT &&
+      args[1]->cmp_type() == STRING_RESULT &&
       agg_arg_charsets_for_comparison(coll, args, 2))
     return;