General Performance recommendation with JOIN clause

A general performance recommendation is to try and avoid JOIN operations that include more than four or five tables. You should always test new JOIN statements, especially those containing a large number of tables or rows.

You need to be especially careful to verify result sets when working with the OUTER JOIN
Operator with more than two tables involved. The Database Engine builds temporary result
Sets from the first JOIN operation, and then uses that result set for the next JOIN operation.