IN vs. JOIN with large rowsets

Question

I\'m wanting to select rows in a table where the primary key is in another table. I\'m not sure if I should use a JOIN or the IN operator in SQL Server 2005. Is there any si

Answer 1

Neither. Use an ANSI-92 JOIN:

SELECT a.*
FROM a JOIN b a.c = b.d

However, it's best as an EXISTS

SELECT a.*
FROM a
WHERE EXISTS (SELECT * FROM b WHERE a.c = b.d)

This remove the duplicates that could be generated by the JOIN, but runs just as fast if not faster