Equivalent of FOUND_ROWS() function in Postgresql

Question

I am doing some paging in my application, returning 20 rows from the database at a time using PostgreSQL's standard OFFSET and LIMIT keywords. For instance, to get page 1 page:

SELECT stuff FROM table WHERE condition ORDER BY stuff OFFSET 0 LIMIT 20

It is a requirement of the application that we also show to the user the total number of records. So, obviously, I can get the total by issuing a separate query:

SELECT COUNT(*) FROM table WHERE condition

But if there are a large number of rows then this is not an optimal solution. I notice that MySQL has a very useful function called FOUND_ROWS() that does exactly what I am looking for:

http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function%5Ffound-rows

Is there an equivalent in PostgreSQL?

score 52 · Accepted Answer · edited Mar 13 '14 at 04:18

52

PostgreSQL has had window functions for a while now which can be used to do many things including counting rows before LIMIT is applied.

Based on the example above:

SELECT stuff,
       count(*) OVER() AS total_count
FROM table
WHERE condition
ORDER BY stuff OFFSET 40 LIMIT 20

edited Mar 13 '14 at 04:18

Mike Chamberlain

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answered Mar 12 '14 at 13:59

Andrew Hacking

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will `count(*) OVER() AS total_count` be executed for every row? e.g. if we have 20 rows, does it mean it will be calculated 20 times, or only once? – tylik Mar 18 '19 at 00:42
It will be executed only once. – Julian Mehnle Sep 23 '20 at 01:45

score 0 · Answer 2 · answered Oct 21 '10 at 06:05

0

There is no equivalent. look at

http://archives.postgresql.org/pgsql-novice/2007-07/msg00108.php

answered Oct 21 '10 at 06:05

Haim Evgi

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score -1 · Answer 3 · edited Jun 18 '23 at 15:54

-1

SELECT
    n_live_tup     
FROM
    pg_stat_user_tables     
WHERE 
    relname = 'table_Name';

edited Jun 18 '23 at 15:54

Rich

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answered Jun 16 '23 at 21:47

Paulo Reis

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Equivalent of FOUND_ROWS() function in Postgresql

3 Answers3

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