Re: Pulling an ID list from a DB, then filtering that list againstanother list of ID's
| From: | CPT John W. Holmes | Date: | Thu, 14 Aug 2003 20:35:18 +0000 |
| Subject: | Re: Pulling an ID list from a DB, then filtering that list againstanother list of ID's | ||
| References: | 1 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-29900@lists.php.net to get a copy of this message | ||
From: "Matt Babineau" <matt@criticalcode.com>
> Got an interesting problem! I have a list of ID's, basically things
> people have viewed on my website. When I pull the viewable items from my
> database, I need to be able to filter out all the ID's people have
> already viewed, so that they only get a list of things they have not
> viewed.
>
> I can think of a way to do this, but it is a nasty loop situation, that
> would probably not be good and tie up significant CPU time. Anyone have
> any suggestions on ways to filter view items from a fresh list that I am
> pulling from my Database?
So you have a "thing_id" and a "user_id". How do you mark the user as having
viewed the "thing"?
I'm thinking a LEFT JOIN is in order here, but need some more info on your
table structure.
---John Holmes...