Deleting rows from SQLite table when no match exists in another table

Question

I need to delete rows from an SQLite table where their row IDs do not exist in another table. The SELECT statement returns the correct rows:

SELECT * FROM ca         


        

Answer 1

Since you going down the route of subquery, might as well get rid of the join altogether and simplify the query:

DELETE FROM cache WHERE id NOT IN (SELECT id from main);