INNER JOIN vs LEFT JOIN performance in SQL Server

Question

I\'ve created SQL command that uses INNER JOIN on 9 tables, anyway this command takes a very long time (more than five minutes). So my folk suggested me to change INNER JOIN

Answer 1

Your performance problems are more likely to be because of the number of joins you are doing and whether the columns you are joining on have indexes or not.

Worst case you could easily be doing 9 whole table scans for each join.