if value is already in the second table do not select
profile_id is varchar
SELECT profile_id
FROM a_messages
WHERE
where profile_id is NOT in profiles
so profiles.profile_id does not exist
because if the value is already profiles table, there is no need to use it
SELECT profile_id
FROM a_messages
WHERE
where profile_id is NOT in profiles
so profiles.profile_id does not exist
because if the value is already profiles table, there is no need to use it
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