fix BIGINT+MEDIUMINT type aggregation

Author: vuvova

mysql-test/r/type_uint.result

@@ -14,3 +14,22 @@ this
 0
 4294967295
 drop table t1;
+create table t1 (a bigint unsigned, b mediumint unsigned);
+insert t1 values (1,2),(0xffffffffffffffff,0xffffff);
+select coalesce(a,b), coalesce(b,a) from t1;
+coalesce(a,b)	coalesce(b,a)
+1	2
+18446744073709551615	16777215
+create table t2 as select a from t1 union select b from t1;
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `a` bigint(20) unsigned DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+select * from t2;
+a
+1
+18446744073709551615
+2
+16777215
+drop table t1, t2;

mysql-test/t/type_uint.test

@@ -15,3 +15,11 @@ select * from t1;
 drop table t1;
 
 # End of 4.1 tests
+
+create table t1 (a bigint unsigned, b mediumint unsigned);
+insert t1 values (1,2),(0xffffffffffffffff,0xffffff);
+select coalesce(a,b), coalesce(b,a) from t1;
+create table t2 as select a from t1 union select b from t1;
+show create table t2;
+select * from t2;
+drop table t1, t2;

sql/field.cc

@@ -359,7 +359,7 @@ static enum_field_types field_types_merge_rules [FIELDTYPE_NUM][FIELDTYPE_NUM]=
   //MYSQL_TYPE_NULL         MYSQL_TYPE_TIMESTAMP
     MYSQL_TYPE_LONGLONG,    MYSQL_TYPE_VARCHAR,
   //MYSQL_TYPE_LONGLONG     MYSQL_TYPE_INT24
-    MYSQL_TYPE_LONGLONG,    MYSQL_TYPE_LONG,
+    MYSQL_TYPE_LONGLONG,    MYSQL_TYPE_LONGLONG,
   //MYSQL_TYPE_DATE         MYSQL_TYPE_TIME
     MYSQL_TYPE_VARCHAR,     MYSQL_TYPE_VARCHAR,
   //MYSQL_TYPE_DATETIME     MYSQL_TYPE_YEAR