MySQL Multi-Table Reference

I’ve got a load of tables within which the records can have a category (identified by the “category_id” field). There’s obviously a “category” table that defines all of these categories, and this is shared by all tables.

Now, if the users wishes to remove a category, I need to check each of the tables to see if it’s ID is used by any of the records. Obviously I could do:

SELECT * FROM event WHERE category_id=’x’;
SELECT * FROM news WHERE category_id=’x’;
.
.
.
SELECT * FROM quicklinks WHERE category_id=’x’;
SELECT * FROM quiz WHERE category_id=’x’;

Ad nauseaum, but is there a way of checking if this id is contained within [I]any[/I] of the tables via a single SQL command?

It would be escpecially useful as some of the tables may not exist, each client has their own database with selected tables contained therein.

Any ideas?

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