> sqlite> select * from a where a=10 group by b; > 10|1 > 10|2 > sqlite> select * from a where a=11 group by b; > 11|2 > 11|3 > > How can I do count equivalent of such a query to find out how many > distinct values of b there are for a given a? (That is get an answer of > 2 in the above)
select count(distinct b) from a where a = 11; Pavel On Fri, May 6, 2011 at 10:03 AM, Matthew Jones <matthew.jo...@hp.com> wrote: > A simple query question that I really ought to know the answer to but don't: > > Given a table with multiple columns in it how do I count how many > entries there are with column A matching some value where column B is > distinct? > > sqlite> create table a (a, b); > sqlite> insert into a values (10, 1); > sqlite> insert into a values (10, 2); > sqlite> insert into a values (10, 2); > sqlite> insert into a values (11, 2); > sqlite> insert into a values (11, 2); > sqlite> insert into a values (11, 3); > sqlite> select * from a where a=10 group by b; > 10|1 > 10|2 > sqlite> select * from a where a=11 group by b; > 11|2 > 11|3 > > How can I do count equivalent of such a query to find out how many > distinct values of b there are for a given a? (That is get an answer of > 2 in the above) > > Thanks > > -- > Matthew Jones > Hewlett-Packard Ltd > Long Down Avenue > Stoke Gifford > Bristol. BS34 8QZ > Tel: +44 (0) 117 312 7490 > Email: matthew.jo...@hp.com<mailto:matthew.jo...@hp.com> > > Hewlett-Packard Limited registered Office: Cain Road, Bracknell, Berks, > RG12 1HN. Registered No: 690597 England > > The contents of this message and any attachments to it are confidential > and may be legally privileged. If you have received this message in > error, you should delete it from your system immediately and advise the > sender. > > To any recipient of this message within HP, unless otherwise stated you > should consider this message and attachments as "HP CONFIDENTIAL". > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
