the results is wrong because of bug in bigint(45) handle column comparing

[ChenPeng2013]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

use test;
source [test.txt](https://github.com/pingcap/tidb/files/8280923/test.txt)
alter table PK_SIGNED_10093 cache;

# you can execute many times to reproduce
select col1, col2 from PK_SIGNED_10093 where col1 > (select max(col1) from PK_SIGNED_10093 t1 where t1.col1 > 0);

2. What did you expect to see? (Required)

MySQL [test]> select col1, col2 from PK_SIGNED_10093 where col1 > (select max(col1) from PK_SIGNED_10093 t1 where t1.col1 > 0);
Empty set (0.00 sec)

3. What did you see instead (Required)

MySQL [test]> select col1, col2 from PK_SIGNED_10093 where col1 > (select max(col1) from PK_SIGNED_10093 t1 where t1.col1 > 0);
+----------------------+--------------------------------------------------------------+
.....
+----------------------+--------------------------------------------------------------+
50 rows in set (0.00 sec)

4. What is your TiDB version? (Required)

Release Version: v6.0.0-alpha-122-g46c43fe
Edition: Community
Git Commit Hash: 46c43febcac0e24bc9f0872e93cf6125db69d93d
Git Branch: master
UTC Build Time: 2022-03-17 01:02:30
GoVersion: go1.17.6
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

[tiancaiamao]

Again, this is neither a subquery nor a bug of table cache...
It's a general one of the UnionScan executor, or you can say it's a planner bug.
Here is the minimal reproduce:

mysql> create table t (id bigint(45) unsigned not null, c varchar(20), primary key(id));
Query OK, 0 rows affected (0.01 sec)

mysql> insert into t values (9734095886065816707, 'a'), (10353107668348738101, 'b'), (0, 'c');
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> begin;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into t values (33, 'd');
Query OK, 1 row affected (0.00 sec)

mysql> select max(id) from t;
+---------+
| max(id) |
+---------+
|      33 |
+---------+
1 row in set (0.00 sec)