Extracting all the id's from a query and saving them as a comma seperated list

[eluser]jtotheb[/eluser]
Php5 is where i'm at so that is great.

I really struggle with the myriad ways of getting data out from AR queries, i find myself getting quite quite lost a lot of the time. I think i need to write myself some form of cheat sheet.

Thanks a lot xwero, i really appreciate your help.