Re: MySQL Query Help

I'm going to jump in and throw in my 2 cents... Have you used dreamweaver? I would suggest Dreamweaver to any new programmer beginning php/mysql. It helped me out tremendously in the beginning. I'm not an advanced programmer with hand coding classes yet, but I can get any job completed for clients with dreamweaver. Custom content management systems, image galleries from mysql etc... Give it a try, It lets you add the the prewritten code and then you can switch to code view and see whats its doing. RD On Nov 20, 2010, at 3:54 PM, Ben Miller wrote: > Hi, > > I'm building a website for a client in which I need to compare their > products, side-by-side, but only include criteria for which all selected > products have a value for that criteria. > > In my database (MySQL), I have a tables named "products","criteria" and > "criteria_values" > > If I have something like > > $selected_product = array("1"=>"Product > 1","2"=>"Product 2"...) // All > products selected for comparison by the user > > I need to get only rows from "criteria" where there is a row in > "criteria_values" matching "criteria.criteria_id" for each > $selected_product > - in other words, if any of the $selected_product does not have a row in > "criteria_values" that matches "criteria.criteria_id", that criteria would > not be returned. I hope that makes sense. > > I've played around with a few join queries, but none have given the desired > results. Best I've been able to come up with so far is to query "criteria" > for each DISTINCT(criteria_id) and then run through each $selected_product > to make sure each has a criteria_value with a matching criteria_id, > eliminating any criteria where the number of criteria_values < > count($selected_product), but this seems pretty inefficient. > > Thanks in advance for any help. > > Ben Miller > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php >