[RBASE-L] - An SQL Q : EXISTS vs IN, Within A Correlated Context (Doesn't this subject text sound like some sort of Seminar Session f/a bunch of PhD's?)

[J. Stephen Wills]

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