James Powell wrote: > SELECT MAX(X) AS MaxX, MAX(X)/MIN(X) AS RatioX > > does the MAX(X) get calculated twice, or does SQLite identify that it > is the same number and do it only once?
At least in version 3.8.0.2, it gets calculated only once. Please note that SQLite can optimize MIN/MAX calculations for indexed columns (<http://www.sqlite.org/optoverview.html#minmax>), but only for extremely simple queries. *If* your X column has an index, you could speed up your query by moving the MIN/MAX into simple subqueries: SELECT (SELECT MAX(X) FROM tab) AS MaxX, (SELECT MAX(X) FROM tab) / (SELECT MIN(X) FROM tab) AS RatioX; Regards, Clemens _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
