如果另一个表中不存在值，则插入值

Question

I would like to check if all values in column releases.id exist in column charts_extended.release_id

If the value does not exist then I want to insert that value in column releases.id into column charts_extended.release_id

Answer 1

You should first come up with query to check whether the id exists in the table, for example:

SELECT id 
FROM releases
 LEFT JOIN charts_extended ON (release_id=releases.id)
WHERE release_id IS NULL;

If you are happy with that, you can proceed into converting it to an INSERT statement:

INSERT INTO charts_extended (release_id) 
SELECT id 
FROM releases
 LEFT JOIN charts_extended ON (release_id=releases.id)
WHERE release_id IS NULL;