select l.b, r.a = l.b from tab l join tab r on l.a = r.b where l.a = 1 ; seems to produce the result you want
"Gabriel B." <[EMAIL PROTECTED]> 29/03/2005 09:30 Please respond to "Gabriel B." <[EMAIL PROTECTED]> To mysql@lists.mysql.com cc Subject help with a mutuality check (good query exercise :) I got stuck in this one, and i belive there's a solution, i just don't happen to see it. i have a table with conections between itens. something like +---+---+ | A | B | +---+---+ | 1 | 2 | | 1 | 3 | | 1 | 4 | | 2 | 1 | +---+---+ i'm trying to solve with one query a way to get all of the relations with 1 on the A colum but having another field, telling me if the relation is mutual. something that would return +---+--------+ | B | mutual | +---+--------+ | 2 | 1 | | 3 | 0 | | 4 | 0 | +---+--------+ Can you think of anything that doesn't involve some big temporary tables or one extra query for every row found on the first one? , Gabriel -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
