fix(query): alter modify col comment need modify when type not modify

[TCeason]

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Summary

create table t1(id varchar, id2 varchar);
Query OK, 0 rows affected (0.060 sec)

MySQL [(none)]> alter table t1 modify id varchar comment 'ss';
Query OK, 0 rows affected (0.246 sec)

MySQL [(none)]> alter table t1 modify id varchar comment 'ss', id2 varchar comment 's3';
Query OK, 0 rows affected (0.079 sec)

After alter:

show create table t1;
+-------+-----------------------------------------------------------------------+
| Table | Create Table                                                          |
+-------+-----------------------------------------------------------------------+
| t1    | CREATE TABLE t1 (
  id VARCHAR NULL,
  id2 VARCHAR NULL
) ENGINE=FUSE |
+-------+-----------------------------------------------------------------------+

Because in
https://github.com/datafuselabs/databend/blob/3aeb2d0290ac004adda4a8e13306b50e33798d4f/src/query/service/src/interpreters/interpreter_table_modify_column.rs#L245

So if new type is same, the schema will always eq with old schema.

So if column type is not modify, the comment will be ignored.

• Fixes Feature: alter table need support modify column comment  #15216

Tests

• Logic Test

Type of change

• Bug Fix (non-breaking change which fixes an issue)

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This change is