While I'm not entirely new with SQL, I am not by any means highly knowledgable.
I'm attempting to write a SQL statement to do the following, and having no luck:
There is only one table, with several fields of metadata including the following.
1 field (integer) that indicates which section the table element is in. (e.g., 1="Illustrations Gallery" 2="Painting Gallery") Call this Field A.
1 field that can be NULL, or can contain the id (pkey) of another entry in the same table indicating a link between them. Call this Field B.
Field B can only contain links (primary keys) from elements that have a specific value of Field A.
I want to select the IDs of "eligable" elements. That is, rows who have the right value of A, and are not present in any other row's value of B.
Therefore: I need a query that says, essentially -
SELECT * from `table` where `A`=X AND `id`=(Doesn't Exist Anywhere in B);