Try a rule or a triger that checks for NOT EXISTS ( select 1 from eyp_listing where group_id = New.group_id and userid != New.userid)
"Rajesh Kumar Mallah." wrote: > > Hi , > > can anyone tell me how can i enforce below in a table. > I want that no more that one distinct userid exists for a given group_id > in the table. > > ie i want 1 to 1 mapping between group_id and userid so that , there shud not be a > single group_id having more that one kind of userid. > > SELECT group_id from eyp_listing group by group_id having count(distinct userid) >> 1 ; > > always returns empty. > > can it be done with some sort of UNIQUE INDEX? > > Regds > MAllah. > > -- > Rajesh Kumar Mallah, > Project Manager (Development) > Infocom Network Limited, New Delhi > phone: +91(11)6152172 (221) (L) ,9811255597 (M) > > Visit http://www.trade-india.com , > India's Leading B2B eMarketplace. > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED]) ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
