MySQL: Delete row if id doesn't exist in other table

I think this is newbie ask. How to delete row if id doesn't exist in other 开发者_如何学JAVAtable? My thought is fetch the ids first and delete. I'm looking for better querying.

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You can set foreign keys to these tables.

More info here

for simple query, here it is:

 DELETE FROM table WHERE (SELECT count(1) FROM table2 WHERE id = table.id) < 1