Re: Efficient way to count rows when using GROUP BY

It worked! SELECT COUNT(*) FROM (SELECT COUNT(*) FROM ad.off_enrol GROUP BY jcu_campus, sub_code) t1 Thank you list -:) Martín Marqués wrote:

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.