On Sat, Nov 12, 2011 at 10:02 PM, Luuk <luu...@gmail.com> wrote:
> Should give same results as:
>
> SELECT * FROM m WHERE
> c IN (SELECT * FROM a) OR
> c IN (SELECT * FROM b)
> AND (c IN (SELECT * FROM b));
>
> Because of the 'OR' on the second line
>
> This can be simplified to:
>
> SELECT * FROM m WHERE
> c IN (SELECT * FROM a) OR
> c IN (SELECT * FROM b);
That's right. Sorry, my query was wrong in the first place. It would
have been more something like:
SELECT * FROM m WHERE
c IN (SELECT docid FROM a WHERE t match "blah") OR
(c IN (SELECT docid FROM b WHERE t match "blah")
AND NOT c IN (SELECT docid FROM a));
e.g. we can either have a match in a, but only a match in b if a does
not have a row with the same docid. Which, in this case, does not
involve any redundant subquery and should be fast. Sorry, my question
was badly stated in the first place. At least your answers helped me
notice it - thanks for that. Of course, if there is any better way to
do this query, I would be glad to know it anyway.
Thanks again!
Alex.
_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
