executor: fix wrong behavior for max/min on ENUM/SET column (#19552)

[ti-srebot]

cherry-pick #19552 to release-4.0

---

What problem does this PR solve?

Issue Number: close #13961

Problem Summary:
max/min produces wrong result on ENUM & SET column.

What is changed and how it works?

What's Changed:
Fix max/min implementation for ENUM/SET type.

How it Works:
Add max/min implementation for ENUM/SET type.

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
  No.
• Need to cherry-pick to the release branch
  No.

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)

create table t3(id int, en enum('b', 'a'));
insert into t3 values (1, 'a'), (1, 'b');

mysql root@127.0.0.1:test> select max(en) from t3 group by id; 
                           select max(en) from t3; 
                                                                                                                                                                                                             
+---------+
| max(en) |
+---------+
| a       |
+---------+
1 row in set
Time: 0.014s

+---------+
| max(en) |
+---------+
| a       |
+---------+
1 row in set
Time: 0.013s
mysql root@127.0.0.1:test>                                                                                                                                                                                   
mysql root@127.0.0.1:test> select min(en) from t3 group by id; 
                           select min(en) from t3; 
                                                                                                                                                                                                             
+---------+
| min(en) |
+---------+
| b       |
+---------+
1 row in set
Time: 0.014s

+---------+
| min(en) |
+---------+
| b       |
+---------+
1 row in set
Time: 0.013s

create table t4(id int, f set('a', 'b', 'c'));
insert into t4 values(1, 'a'), (2, 'b'), (1, 'a,b,c');

mysql [email protected]:test> select max(f) from t4; 
                           select max(f) from t4 group by id; 
                                                                                                                                                                                                             
+--------+
| max(f) |
+--------+
| a,b,c  |
+--------+
1 row in set
Time: 0.014s

+--------+
| max(f) |
+--------+
| a,b,c  |
| b      |
+--------+
2 rows in set
Time: 0.013s

mysql [email protected]:test> select min(f) from t4; 
                           select min(f) from t4 group by id; 
                                                                                                                                                                                                             
+--------+
| min(f) |
+--------+
| a      |
+--------+
1 row in set
Time: 0.015s

+--------+
| min(f) |
+--------+
| a      |
| b      |
+--------+
2 rows in set
Time: 0.014s

Side effects

• MySQL Compatibility
  MySQL produce MIN/MAX result on string value of ENUM/SET column, rather than index value. Which is in-consist with manual, and considered as a known issue.

In MIN(), MAX(), and other aggregate functions, MySQL currently compares ENUM and SET columns by their string value rather than by the string's relative position in the set.

Release note

• Fix wrong behavior for max/min on ENUM/SET column.

[ti-srebot]

/run-all-tests

[qw4990]

LGTM

[qw4990]

/run-all-tests

[SunRunAway]

LGTM

[SunRunAway]

/merge

[ti-srebot]

/run-all-tests

[ti-srebot]

@ti-srebot merge failed.

[qw4990]

/run-all-tests