Question

Here’s my query:

SELECT * 
    FROM designs AS d
    LEFT JOIN categories AS c
       ON d.category = c.category
    GROUP BY d.name ASC LIMIT 0, 10

I’d like return the number of rows found WITHOUT the limit condition in place. Here’s my line of thinking:

SELECT SQL_CALC_FOUND_ROWS '0', *
    FROM designs AS d
    LEFT JOIN categories AS c
       ON d.category = c.category
    GROUP BY d.name ASC LIMIT 0, 10
UNION 
SELECT '1', FOUND_ROWS() 

This doesn’t work. I get a column # mismatch. How would I modify the query to work?

Answer 1

Your first select, is a:

SELECT '0', *

I don’t know how many columns ‘*’ is (at least 3, d.category, d.name, c.category), but your second query (after the union) should have the same number of columns. Now you only return two columns in your second query.

I also saw in the documentation, you should use an UNION ALL instead of UNION, I quote:

The value of FOUND_ROWS() is exact only if UNION ALL is used. If UNION without ALL is used, duplicate removal occurs and the value of FOUND_ROWS() is only approximate.