Invalid use of group function. But not using group - mysql

Question

I am trying to join a table into forcing only to show the results of voucherroll that have more than 0 not printed vouchers.
But now I am getting the message that i am using a group function wrong. However, I think I'm not using group by at all.
Any ideas?
SELECT *
FROM voucherroll INNER JOIN voucher ON voucherroll.id = voucher.id_voucherroll
WHERE voucher.printed = 0
AND Count(voucher.id > 0)
An updated explanation:
There are multiple rolls, with multiple vouchers.
if vouchers are printed, they are not supposed to be shown.
I want every roll, where the not printed vouchers are more than 0

Answer 1

You are using count() and it doesn't belong in where.
Perhaps this is your intention?
SELECT *
FROM voucherroll INNER JOIN
voucher
ON voucherroll.id = voucher.id_voucherroll
WHERE voucher.printed = 0 AND voucher.id IS NOT NULL;
It would be unusual, though, for something called id to take on NULL values.
EDIT:
I think this is what you want:
SELECT vr.*
FROM voucherroll vr
WHERE EXISTS (SELECT 1
FROM voucher v
WHERE vr.id = v.id_voucherroll and
v.printed = 0
)
If you want more than 1, then use the less efficient:
SELECT vr.*
FROM voucherroll vr
WHERE (SELECT COUNT(*)
FROM voucher v
WHERE vr.id = v.id_voucherroll and
v.printed = 0
) > 1;

Answer 2

Try to use subquery to count as below:
SELECT *
FROM voucherroll
INNER JOIN voucher ON voucherroll.id = voucher.id_voucherroll
WHERE voucher.printed = 0
AND (select count(v.id)
from voucher v
where voucherroll.id = v.id_voucherroll ) > 0
You can't use count in where clause. It is possible in having clause, but you need to use group by.