Question

I am trying to count row numbers on an another table and use HAVING to select only rows greater than 0.

SELECT COUNT(t3.ID),t1.ID,t2.sell,t1.date
FROM `album` t1 
INNER JOIN `members` t2 ON t2.aID = t1.ID 
INNER JOIN `table` t3 ON t3.rID = t1.ID 
WHERE t1.date <= '$dt' AND t2.sell = '1'
ORDER BY t1.date DESC
HAVING COUNT(t3.ID) > 0

It doesnt work. where am i wrong ?
Thanks

Answer 1

You need a GROUP BY clause so that MySQL knows how to group the data when you’re using aggregate functions such as COUNT.

SELECT COUNT(t3.ID),t1.ID,t2.sell,t1.date
FROM `album` t1 
INNER JOIN `members` t2 ON t2.aID = t1.ID 
INNER JOIN `table` t3 ON t3.rID = t1.ID 
WHERE t1.date <= '$dt' AND t2.sell = '1'
GROUP BY t1.ID,t2.sell,t1.date
HAVING COUNT(t3.ID) > 0
ORDER BY t1.date DESC

For more information, see this.