On Mon, May 20, 2013 at 12:59:45PM +0100, Paul Sanderson scratched on the wall: > I have a table of the form > > create table tab (num int1 unique, num2, int) > > for each row for num2 there is usually a matching num1. But not always. > > I want to identify each row where num2 does not have a matching num1 > > example data might be > > num1 num2 > 1 3 > 2 3 > 3 2 > 4 1 > 5 11 > 6 3 > 7 9 > > in this example my query would return rows 5 and 7 as there is no match on > num1 for 11 and 9
Join the table to itself using an outer join on the condition that num2 == num1. Look for rows where num1 is NULL, indicating no join was found. Only works if num1 is never NULL in the DB. I need to run. Perhaps someone else can provide an example if that's not making sense. -j -- Jay A. Kreibich < J A Y @ K R E I B I.C H > "Intelligence is like underwear: it is important that you have it, but showing it to the wrong people has the tendency to make them feel uncomfortable." -- Angela Johnson _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
