Need Help with Subquery Possibilities

jjfletch · #1 (**permalink**) 12-05-04, 12:35

Hi, I wanted to use a subquery, as in:

Code:

SELECT * FROM pending WHERE username = (SELECT username FROM ratings);

But have learned subqueries are only available in MySQL 4.21 or later...

So...

I've tried to use the following query:

Code:

SELECT ratings.username,pending.username FROM 
ratings,pending WHERE ratings.username="jjfjunk" OR
pending.username="jjfjunk";

But this returns an empty set, even though I know that the username exists in the ratings table.

Am I missing something?

Pat Phelan · #2 (**permalink**) 12-05-04, 13:35

I'd use:

Code:

SELECT ratings.username,pending.username
   FROM pending 
   INNER JOIN ratings
      ON (ratings.username = pending.username)
   WHERE  'jjfjunk' = pending.username

I suspect that the cartesian join simply might not have returned before you gave up, not that it was truly an empty result set. You could leave off the WHERE condition to get a query that behaves like your original query that used a sub-query.

-PatP

Internet Services

Web Development

Digital Marketing

Consumer Tech