OK, thanks. Do you mean that is only valid if there are no rows where all columns are NULL? In any case, I can see that this optimization (in SQLite) is just not worth the trouble.
RBS On Fri, Oct 2, 2015 at 6:02 PM, Richard Hipp <drh at sqlite.org> wrote: > On 10/2/15, Bart Smissaert <bart.smissaert at gmail.com> wrote: > > > > Unless I am mistaken here this is done with a SQL like this: > > > > SELECT COUNT(*) AS UNIQUE_ROWS > > FROM (SELECT DISTINCT * FROM TABLE1) > > > > But if we take advantage of the fact that this table has a unique index > on > > all the fields of the table > > we can simply do this SQL: > > > > SELECT COUNT(*) FROM TABLE1 > > > > No. That is only valid if all columns are individually NOT NULL. > > -- > D. Richard Hipp > drh at sqlite.org > _______________________________________________ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >
