DB2 query processing order

When constructing a sql statement on DB2 , keep in mind the processing order of the various parts  of the sql statement.This could allow significant performance gains

FROM

JOIN ON

WHERE clause

GROUP BY and aggregate

HAVING clause

SELECT

ORDER BY

FETCH FIRST

For example, you could consider the initial dataset brought in by the FROM clause , and the WHERE clause.

Or could you create more efficient JOIN ON clauses?

 Ref:Jack Vamvas(http://www.dba-db2.com)