bug: UNION clause return error: UNION of non-matching columns (column no 0)

[davidshiz]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Please confirm if bug report does NOT exists already ?

• I confirm there is no existing issue for this

Describe the problem

If the fields use other data type, the same union query is supported, so this problem should be a bug !

mysql> CREATE TABLE cs1 (d1 DECIMAL(17), d2 DECIMAL(17,10), d3 DECIMAL(17,17)) ;
Query OK, 0 rows affected (0.21 sec)

mysql> INSERT INTO cs1 VALUES (125, 1.25, 0.125);
Query OK, 1 row affected (0.03 sec)

mysql> INSERT INTO cs1 VALUES (-125, -1.25, -0.125);
Query OK, 1 row affected (0.00 sec)

mysql> select * from cs1;
+------+---------------+----------------------+
| d1   | d2            | d3                   |
+------+---------------+----------------------+
|  125 |  1.2500000000 |  0.12500000000000000 |
| -125 | -1.2500000000 | -0.12500000000000000 |
+------+---------------+----------------------+
2 rows in set (0.00 sec)

mysql> select * from cs1 union select * from cs1;
+------+---------------+----------------------+
| d1   | d2            | d3                   |
+------+---------------+----------------------+
|  125 |  1.2500000000 |  0.12500000000000000 |
| -125 | -1.2500000000 | -0.12500000000000000 |
+------+---------------+----------------------+
2 rows in set (0.00 sec)


mysql> SELECT d1, d1, d2 FROM cs1 UNION SELECT d2, d3, d3 FROM cs1;
ERROR 1105 (HY000): The query includes syntax that is not supported by the storage engine. Tianmu: UNION of non-matching columns (column no 0) .

Expected behavior

No response

How To Reproduce

No response

Environment

[root@stonedb-test bin]# ./mysqld --version
./mysqld  Ver 5.7.36-StoneDB-v1.0.1 for Linux on x86_64 (build-)
build information as follow:
        Repository address: https://github.com/stoneatom/stonedb.git:stonedb-5.7-dev
        Branch name: stonedb-5.7-dev
        Last commit ID: 12fa952
        Last commit time: Date:   Sat Jun 3 10:07:20 2023 +0800
        Build time: Date: Mon Jun  5 08:49:16 UTC 2023

Are you interested in submitting a PR to solve the problem?

• Yes, I will!

[adofsauron]

既然已经成功的解决了客户POC的问题 #1873 ， 没有理由不顺带着解决这个类似的问题

[adofsauron]

但是这个问题的场景又有所不同

(gdb) p type2
$3 = {
  type = Tianmu::common::ColumnType::NUM, 
  unsigned_flag_ = false, 
  precision = 17, 
  scale = 10, 
  internal_size = 8, 
  display_size = 19, 
  collation = {
    collation = 0x446fae0 <my_charset_latin1>, 
    derivation = DERIVATION_NUMERIC, 
    repertoire = 3
  }, 
  fmt = Tianmu::common::PackFmt::DEFAULT, 
  flag = std::bitset
}

[adofsauron]

decimal在mysql官方的文档做下备忘录

https://dev.mysql.com/doc/refman/5.7/en/fixed-point-types.html

[adofsauron]

问题就在乎，这个精度，是写了魔数不做支持，但是为什么能创建表属性成功？还能插入数据？
如果依据这样的逻辑，那么在创建临时表的时候，就也不能做限制了

d2 DECIMAL(17,10)

[adofsauron]

所以根据以上的逻辑，在临时表中做和物理表相同的逻辑对策

[adofsauron]

问题被成功的解决