From d027dd7c0d9d2d105e712e6ff89a4483a7dfc177 Mon Sep 17 00:00:00 2001
From: "evgen@moonbone.local" <>
Date: Wed, 7 Jun 2006 01:10:23 +0400
Subject: Fixed bug#15962: CONCAT() in UNION may lead to a data trucation.

To calculate its max_length the CONCAT() function is simply sums max_lengths
of its arguments but when the collation of an argument differs from the
collation of the CONCAT() max_length will be wrong. This may lead to a data
truncation when a tmp table is used, in UNIONS for example.

The Item_func_concat::fix_length_and_dec() function now recalculates the
max_length of an argument when the mbmaxlen of the argument differs from the
mbmaxlen of the CONCAT().
---
 mysql-test/t/func_concat.test | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'mysql-test/t/func_concat.test')

diff --git a/mysql-test/t/func_concat.test b/mysql-test/t/func_concat.test
index 37fc0e105b8..42201961222 100644
--- a/mysql-test/t/func_concat.test
+++ b/mysql-test/t/func_concat.test
@@ -53,3 +53,11 @@ select 'a' union select concat('a', -0.0);
 select 'a' union select concat('a', -0.0000);
 
 # End of 4.1 tests
+
+#
+# Bug#15962: CONCAT() in UNION may lead to a data trucation.
+#
+create table t1(f1 varchar(6)) charset=utf8;
+insert into t1 values ("123456");
+select concat(f1, 2) a from t1 union select 'x' a from t1;
+drop table t1;
-- 
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