2006/4/8, Philippe Poelvoorde <[EMAIL PROTECTED]>: > Hi, > > 2006/4/8, Dan Buettner <[EMAIL PROTECTED]>: > > Seems like what you're looking for is a way to query your database > > more efficiently/quickly, and still find all links in either > > direction. > > > > I think the use of a UNION statement should allow this. Basically > > write your query twice, joining on id1 the first time and id2 the > > second time, with "UNION" in the middle. > > To select reciprocal friends of Dan (that is a friends relationship in > both ways), I would do that : > select p.name from friends f1, friends f2, people p > where p.peopleid=f1.id1 and f1.id2=1 > AND f1.id2=f2.id1 > AND f1.id1=f2.id2 > UNION select p.name from friends f1, friends f2, people p > where p.peopleid=f1.id2 and f1.id1=1 > AND f1.id1=f2.id2 > AND f1.id2=f2.id1; > > +------+ > | name | > +------+ > | Matt | > +------+ > > But I don't think it's the best solution in term of performance :)
Sorry, can anyone comment this query ? How would you find the list of symetric friend of Dan ? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
