SQL_CALC_FOUND_ROWS equivalent in PostgreSQL

https://www.postgresql.org/message-id/1185863074.10580.91.camel%40linda.lfix.co.uk

On Tue, 2007-07-31 at 09:22 +0800, Matt Arnilo S. Baluyos (Mailing
Lists) wrote:

Hello everyone,

I would like to use PostgreSQL with the SmartyPaginate plugin of the
Smarty template engine.

In the examples on the documentation, the following two queries are used:

SELECT SQL_CALC_FOUND_ROWS * FROM mytable LIMIT X,Y
SELECT FOUND_ROWS() as total

What the SQL_CALC_FOUND_ROWS does is that it allows the FOUND_ROWS()
function to return the total rows if the first query didn't have the
LIMIT.

SQL_CALC_FOUND_ROWS and FOUND_ROWS() are MySQL features.

Is there an equivalent function in PostgreSQL for this or perhaps a
workaround?

There is no equivalent. Use

BEGIN;
SELECT * FROM mytable OFFSET X LIMIT Y;
SELECT COUNT(*) AS total FROM mytable;
END;

(To ensure consistent results, both queries should be done in a single
transaction.)

If you are repeating the query multiple times for separate pages, it
would be more efficient to do the COUNT() selection first and not repeat
it for each page. You could use a cursor to go back and forth through
the results while doing the query only once.