On Sat, Dec 17, 2016 at 10:25 AM, Arup Rakshit <aruprakshit1...@outlook.com> wrote:
> Hi, > > Here is a sample data from table "quiz_results": > > id | question_id | user_id > ----+-------------+------------ > 2 | 25 | 5142670086 > 3 | 26 | > 4 | 26 | > 5 | 27 | > 6 | 25 | 5142670086 > 7 | 25 | 5142670086 > 8 | 25 | 5142670086 > 9 | 26 | > 10 | 40 | 5142670086 > 11 | 29 | 5142670086 > > > As you see above question id 25 appeared more than once. This is basically > a quiz result table where for users as they answered. question_id 25 always > the first questions. Any user can go though the quiz N number of time. So, > I want to find the last occurrence of the question_id 25 for any specific > user in the table, and select that and all answers the users gave after > this till the end of the quiz. Any idea how to solve it in a single > efficient query. My all try didn't work out. > > > > -------------------- > Regards, > Arup Rakshit > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general > Will this work? WITH quest AS (SELECT id, question_id, user_id FROM questions WHERE user_id = 5142670086 --> substitute any user_id value AND question_id = 25 --> substitute any question_id value ORDER BY 1, 2, 3) SELECT * FROM quest WHERE id IN (SELECT max(id) FROM quest); -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.
