Muris Pucic wrote:
> -- The query below works, even though there is no column "first_name" in
> TABLE2. This should return an error but it does not, it returns all rows
> from TABLE1. This query should not evaluate correctly even when aliases are
> not used because it can be misleading.
>
> SELECT * FROM TABLE1 WHERE first_name IN (SELECT first_name FROM TABLE2)
Nope, it's working as expected. The first_name in the subquery is
referring to the first_name column in the outer query. While it looks
strange in a context like that, it's not an error. You wouldn't be able
to write correlated subqueries otherwise, e.g:
SELECT * FROM TABLE1 WHERE EXISTS (SELECT 1 FROM TABLE2 WHERE first_name
= last_name)
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
