[Proposal] Support Alter Table Clause For External Table(Eg:ODBC table, ES table).

[HappenLee]

Motivation

At present, many users need to access the external table through Doris. Like ODBC table, ES Table, But now Doris only support alter clause for OLAP Table at present. This problem makes it difficult for users of external table.

So should we support Alter Table Clause as OLAP Table.

Describe the solution you'd like

Support 5 alter operation user always need to use：

• RENAME
• ADD COLUMN
• DROP COLUMN
• MODIFY COLUMN
• REORDER COLUMN

Do not support other operation like "rollup, parttition", if user use some operation the external table do not support:

ERROR 1064 (HY000): errCode = 2, detailMessage = ODBC [oralce_1] do not support ADD_ROLLUP clause now