expense - see http://stackoverflow.com/questions/2065754/is-there-any-general-rule-on-sql-query-complexity-vs-performance http://stackoverflow.com/questions/206

expense - see http://stackoverflow.com/questions/2065754/is-there-any-general-rule-on-sql-query-complexity-vs-performance http://stackoverflow.com/questions/2065754/is-there-any-gene... which actually shows it fairly well. (the stackoverflow response is a much better response than i could have written, hence the link)