Re: Efficient way to count rows when using GROUP BY

El Dom 26 Jun 2005 07:39, Ross Honniball escribió: > Hi All, > > I use > > SELECT COUNT(*) FROM whatever WHERE whatever > > to determine how many rows a particular query will return (then use this count to assist with pagination). > > The problem is that this does not work if the query contains a GROUP BY statement as, of course, > the query will return many rows each with a count by each grouping. > > Does anyone know an efficient way to determine the number of ROWS a query with a GROUP BY > statement will return (without just executing the entire query with no LIMIT statement)? You are not stating which database you are working with, but I would do this (don't know if it's efficient, but it'll work): SELECT sum(count) FROM (SELECT COUNT(*) AS count FROM whatever WHERE whatever) t1; Hope it helps. -- select 'mmarques' || '@' || 'unl.edu.ar' AS email; --------------------------------------------------------- Martín Marqués | Programador, DBA Centro de Telemática | Administrador Universidad Nacional del Litoral ---------------------------------------------------------