Mysql deletes a duplicate record of a field in a table _mysql

For example, table: event (id int () auto_increment primary KEY,
Sid Int (a) NOT NULL,
Detail text)

I would like to delete the SID duplicate record in the table event, is there such an SQL statement? or by other means?

Copy Code code as follows:

Delete from event as E
Where ID!= (select min (id) from event where Sid=e.sid);

Or

Copy Code code as follows:

Delete from event
Where Sid not in (select SID, Min (id) as mid to Event Group by SID)

It should be useful code.

Copy Code code as follows:

Alter Ignore table event add unique index idu_sid (SID);
ALTER TABLE event DROP INDEX idu_sid;