I want to copy structure of a SET table to a New table as MULTISET. Is there any way we can do this?
Sure. Simply use:
CREATE MULTISET TABLE <new-multiset-table> AS <existing-set-table>;
If the existing table has any UNIQUE indexes (or other UNIQUE constraints), you'll probably want to override them.
For more information, see:
Go to the DDL of the SET table using SHOW command, copy that whole statement, replace SET with MULTISET with a new table name.