From: hsv Date: February 5 2013 8:10pm Subject: RE: IF and CASE List-Archive: http://lists.mysql.com/mysql/228935 Message-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" >>>> 2013/02/05 17:06 +0000, Rick James >>>> As a Rule of Thumb, function evaluation time is not significant to the overall time for running a query. (I see IF and CASE as 'functions' for this discussion.) Do you have evidence that says that IF is slower? Perhaps using BENCHMARK()? <<<<<<<< Not BENCHMARK: I did a query with one, and also with the other, and repeated each at least a dozen times, and looked at the reported time. The IF-variant took ever so slightly more time than the CASE-variant. But which of the arguments are always evaluated, which only at need? This could be a difference, that IF s arguments always are, CASE s only at need.