mysql query to check if this data exists in any of tables

[LetItBe]

hi there

i have two mysql tables (for example `table1` and `table2`). there is the same field called `id` in both of these tables. i need a query that checks if variable $id exists in any of these tables at the `id` column.

thanks for an attention.

[Birdman]

SELECT * FROM table1 t1, table2 t2 WHERE t1.id=__YOUR_VAL__ OR t2.id=__YOUR_VAL__

That should do it.

[FalseDawn]

No, that will return a Cartesian product of the 2 tables, which is not what you want.

A Union will do the job:

SELECT 1 FROM DUAL WHERE EXISTS (SELECT * FROM table1 WHERE id=$id)
UNION
SELECT 1 FROM DUAL WHERE EXISTS (SELECT * FROM table2 WHERE id=$id)

...but you may as well just write 2 separate queries

[edited by: FalseDawn at 4:12 pm (utc) on April 7, 2007]