Can I get better performance using a JOIN or using EXISTS?

Question

I have two tables Institutions and Results and I want to see if there are any results for institutions that way I can exclude the ones that don\'t have results.

Can

Answer 1

If you're referring to using a left (or right) outer join or a not exists subquery, I'm fairly certain the left outer join wins performance-wise. For example:

SELECT t1.* FROM table1 t1 LEFT OUTER JOIN table2 t2 ON t1.id = t2.id WHERE t2.id IS NULL

The above should be quicker than the equivalent sub-query, and if you're referring specifically to exists - well, where structure allows, an inner join will always be the preferred option.