From 42155a35d1baadf047d80eeb4594c2c15cc17cad Mon Sep 17 00:00:00 2001
From: unknown <jimw@mysql.com>
Date: Fri, 28 Oct 2005 18:12:57 -0700
Subject: [PATCH] Fix bug in handling of decimal fields in UNION statements
 that could cause a crash or write to an incorrect memory location. (Bug
 #14216)

mysql-test/r/union.result:
  Update results
mysql-test/t/union.test:
  Add regression test
sql/item.cc:
  Set max_length for decimal fields correctly
---
 mysql-test/r/union.result | 26 ++++++++++++++++++++++++++
 mysql-test/t/union.test   | 18 ++++++++++++++++++
 sql/item.cc               |  7 +++++--
 3 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/mysql-test/r/union.result b/mysql-test/r/union.result
index 318bfa2cda8..a9b2345d834 100644
--- a/mysql-test/r/union.result
+++ b/mysql-test/r/union.result
@@ -1253,3 +1253,29 @@ id
 5
 99
 drop table t1;
+create table t1 (f1 decimal(60,25), f2 decimal(60,25));
+insert into t1 values (0.0,0.0);
+select f1 from t1 union all select f2 from t1;
+f1
+0.0000000000000000000000000
+0.0000000000000000000000000
+select 'XXXXXXXXXXXXXXXXXXXX' as description, f1 from t1
+union all
+select 'YYYYYYYYYYYYYYYYYYYY' as description, f2 from t1;
+description	f1
+XXXXXXXXXXXXXXXXXXXX	0.0000000000000000000000000
+YYYYYYYYYYYYYYYYYYYY	0.0000000000000000000000000
+drop table t1;
+create table t1 (f1 decimal(60,24), f2 decimal(60,24));
+insert into t1 values (0.0,0.0);
+select f1 from t1 union all select f2 from t1;
+f1
+0.000000000000000000000000
+0.000000000000000000000000
+select 'XXXXXXXXXXXXXXXXXXXX' as description, f1 from t1
+union all
+select 'YYYYYYYYYYYYYYYYYYYY' as description, f2 from t1;
+description	f1
+XXXXXXXXXXXXXXXXXXXX	0.000000000000000000000000
+YYYYYYYYYYYYYYYYYYYY	0.000000000000000000000000
+drop table t1;
diff --git a/mysql-test/t/union.test b/mysql-test/t/union.test
index 6a54909536a..1f6fc2c8d3b 100644
--- a/mysql-test/t/union.test
+++ b/mysql-test/t/union.test
@@ -756,4 +756,22 @@ select 99 union all select id from t1 order by 1;
 select id from t1 union all select 99 order by 1;
 drop table t1;
 
+# 
+# Bug #14216: UNION + DECIMAL wrong values in result
+#
+create table t1 (f1 decimal(60,25), f2 decimal(60,25));
+insert into t1 values (0.0,0.0);
+select f1 from t1 union all select f2 from t1;
+select 'XXXXXXXXXXXXXXXXXXXX' as description, f1 from t1
+union all
+select 'YYYYYYYYYYYYYYYYYYYY' as description, f2 from t1;
+drop table t1;
+create table t1 (f1 decimal(60,24), f2 decimal(60,24));
+insert into t1 values (0.0,0.0);
+select f1 from t1 union all select f2 from t1;
+select 'XXXXXXXXXXXXXXXXXXXX' as description, f1 from t1
+union all
+select 'YYYYYYYYYYYYYYYYYYYY' as description, f2 from t1;
+drop table t1;
+
 # End of 4.1 tests
diff --git a/sql/item.cc b/sql/item.cc
index 642a0ccf1b4..56f0beeeb44 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -3274,8 +3274,11 @@ bool Item_type_holder::join_types(THD *thd, Item *item)
     {
       int delta1= max_length_orig - decimals_orig;
       int delta2= item->max_length - item->decimals;
-      max_length= min(max(delta1, delta2) + decimals,
-                      (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7);
+      if (fld_type == MYSQL_TYPE_DECIMAL)
+        max_length= max(delta1, delta2) + decimals;
+      else
+        max_length= min(max(delta1, delta2) + decimals,
+                        (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7);
     }
     else
       max_length= (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7;