create table show comment

[BohuTANG]

Summary

mysql> create table t1(a INT comment 'acomment') comment='mytable';
Query OK, 0 rows affected (0.03 sec)
Read 0 rows, 0 B in 0.007 sec., 0 rows/sec., 0 B/sec.

mysql> show create table t1;
+-------+------------------------------------------------------------------+
| Table | Create Table                                                     |
+-------+------------------------------------------------------------------+
| t1    | CREATE TABLE `t1` (
  `a` Int32, -- no comments here
) ENGINE=FUSE COMMENT='mytable' |
+-------+------------------------------------------------------------------+

[sunisdown]

/assignme

[sunisdown]

@BohuTANG I have no knowledge about query engine, so I want to pick this issue up and try to understand how query works, but when I check this issue, it seems that we haven't store the comments for field.

databend_query::catalogs::impls::database_catalog: Create table from req:CreateTableReq { if_not_exists: false, tenant: "admin", db_name: "default", table_name: "t1", table_meta: TableMeta { schema: DataSchema { fields: [DataField { name: "a", data_type: Int32, nullable: false }], metadata: {} }, engine: "FUSE", engine_options: {}, options: {"comment": "mytable", "database_id": "1"}, created_on: 2022-04-19T08:24:11.965435Z } }

Is the metadata field suitable for storing the comment?
https://github.com/datafuselabs/databend/blob/d18c5a438204758c52021b2047c19a17b03421bb/common/datavalues/src/data_schema.rs#L27-L31

[sunisdown]

got the root cause.
seems that plan_parser doesn't handle the column comments
https://github.com/datafuselabs/databend/blob/2ca3014d8a8dc41b5ef0ec16780ea4c69e164ece/query/src/sql/statements/statement_create_table.rs#L167-L178

will add it.
by the way, this is a perfect issue for me, as it made me look in both the parse and query plan code, two areas I hadn't touched before.

[BohuTANG]

@sunisdown
Sorry, I missed this comment, glad to see that you found it.

[wubx]

MySQL [(none)]> create table t1(a INT comment 'acomment');
ERROR 1105 (HY000): Code: 1022, displayText = COMMENT 'acomment' column option is not supported, please do not specify them in the CREATE TABLE statement.
MySQL [(none)]> select version();
+-----------------------------------------------------------------------------------------+
| @@version()                                                                             |
+-----------------------------------------------------------------------------------------+
| 8.0.26-v0.7.74-nightly-a556243-simd(rust-1.63.0-nightly-2022-06-06T16:24:09.098868778Z) |
+-----------------------------------------------------------------------------------------+
1 row in set (0.002 sec)

[BohuTANG]

@wubx
This issue has not started yet.

[wubx]

I see you can create a table with comments, but my databend version can't do that.
Do I need a new issue?

[sunisdown]

e you can create a table with comments, but my databend version can't do that.
Do I need a new issue?

It's the same issue, we can create table with table comments, but column comments are not support @wubx

[johnhaxx7]

Seems like this issue is resolved in the linked ticket, good to close?

[BohuTANG]

#5952