JOINS, EXISTS or IN which is better? Few questions on SQL

Question

I have few questions on SQL..

1. How to analyze the performance of a query? Any software, inbuilt features of MSSQL server 2005/2008?

2. What shou

Answer 1

3: I would expect an IN or EXIST clause to be flattened to a JOIN by the database engine, so there shouldn't be a difference in performance. I don't know about SQL Server, but in Oracle you can verify this by checking the execution plan.