afonit wrote >> gender participants answer1_avg answer2_avg >> n 3 12 3 >> m 5 4 12 >> f 7 15 23 Are you sure this is what you want? Since there are two columns you will have to either use a CASE or a sub-select to facilitate calculating the values for each of the columns. SELECT gender, answer1_avg, answer2_avg FROM (SELECT DISTINCT gender FROM ...) gn LEFT JOIN (SELECT gender, answer1_avg FROM ...) ans1 USING (gender) LEFT JOIN (SELECT gender, answer2_avg FROM ...) ans2 USING (gender) You could also try learning "crosstab" from the "tablefunc" extension: http://www.postgresql.org/docs/9.3/interactive/tablefunc.html I do not see how a single "participant count" column will provide a meaningful piece of data... David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/Not-able-to-understand-how-to-write-group-by-tp5810250p5810279.html Sent from the PostgreSQL - general mailing list archive at Nabble.com.
