Steve, I have found that very often EXISTS is lots faster. Both are valid SQL.
IN is often the more compact syntax. I often use SELECT DISTINCT in my IN sub-select to speed things up. Here's some interesting reading: http://www.firstsql.com/iexist2.htm Dennis McGrath --- "J. Stephen Wills" <[EMAIL PROTECTED]> wrote: > Have anyone's thoughts meandered (perhaps needlessly and w/o > justification) to the difference(s) between the use of an > EXISTS-clause > versus an IN-clause in a SELECT-statement? This has begun to consume > more of my available (mental) clock-ticks the past few days. Now, > understand, I'm probably truly twisted as there is no task in my > current > work that requires me to use either approach ; so, it's nothing more > than insane curiosity, idle minds/hands ... > > Anyway, the reason I began to wonder is that when I've used > correlated > EXISTS-clauses or correlated IN-clauses, unless I recall mistakenly, > the > result-sets were equal. > > Am I wrong or missing something? > > Umm, if you have time, thanks, > Steve (infuriatingly curious) in Memphis >
