[Bug]: refine error messages for features that will never be implemented

[daviszhen]

Is there an existing issue for the same bug?

• [X] I have checked the existing issues.

Environment

- Version or commit-id (e.g. v0.1.0 or 8b23a93):
- Hardware parameters:
- OS type:
- Others:

Actual Behavior

Operator '+' with parameters [VARCHAR VARCHAR] will be implemented in future version.

Expected Behavior

No response

Steps to Reproduce

No response

Additional information

No response

[dengn]

move to 0.6

[aressu1985]

mysql> select 'a' + 'b'; +-------+ | a + b | +-------+ | ab | +-------+ 1 row in set (0.00 sec)

mysql> select NULL + 'b'; +----------+ | null + b | +----------+ | NULL | +----------+ 1 row in set (0.00 sec)

mysql> create table bb(a char, b varchar(10)); Query OK, 0 rows affected (0.01 sec)

mysql> insert into bb values('a','b'),('aa','cc'); Query OK, 2 rows affected (0.00 sec)

mysql> select a + b from bb; ERROR 20203 (HY000): invalid argument operator +, bad value [CHAR CHAR] mysql> select b + b from bb; +-------+ | b + b | +-------+ | bb | | cccc | +-------+ 2 rows in set (0.00 sec)