Yonah Russ <[EMAIL PROTECTED]> wrote:
> Hi,
> I have two tables- books and copies
>
> every book has an id in the books table
> every copy of a book has the books id and a copy id in the copies table
> (1 row per copy)
>
> I want a list of all the books that don't have any copies meaning all
> the book id's in books that don't match any book id's in copies.
>
> how can I do this?
Use LEFT JOIN. For example:
SELECT .. FROM book_table LEFT JOIN copy_table
ON book_table.id=copy_table.book_id
WHERE copy_table.book_id IS NULL;
http://dev.mysql.com/doc/mysql/en/Rewriting_subqueries.html
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