Getting SUM() from multiple tables with conditions - mysql

Question

I am trying to get the due_amount from two tables that is invoices and offline_invoice.
The condition is; status not like 'paid%'. I am working with this query
select
(sum(i.total_amount) + sum(oi.invoice_amount)) - (sum(i.paid_amount) + sum(oi.paid_amount)) due_amount
from
{CI}invoices i
left join
{CI}offline_invoice oi ON oi.customer_id = i.customer_id
where
i.customer_id = ?
and i.status not like 'paid%'
group by i.customer_id
But i don't know how do i use condition on joined table({CI}offline_invoice)? I have to use the same condition(status not like 'paid%') on it.

Answer 1

Just add the and to the ON clause too
left join
{CI}offline_invoice oi ON oi.customer_id = i.customer_id
AND oi.status not like 'paid%'
where
i.customer_id = ?
and i.status not like 'paid%'
However, I'm not sure how this is going to work for you without possible Cartesian impact. Say you have 10 current invoice and 10 and 6 offline invoices. I would do two separate pre-aggregates joined by their customer ID... unless the off-line invoice has the same invoice ID as current (such as archive purposes)
select
CurInvoices.Customer_ID,
CurInvoices.InvBalance + COALESCE( OIInvoices.OIBalance, 0 ) as AllBalanceDue
from
( select i.customer_id,
sum( i.total_amount - i.paid_amount ) as invBalance
from
{CI}invoices i
where
i.customer_id = ?
and i.status not like 'paid%'
group by
i.customer_ID ) as CurInvoices
LEFT JOIN
( select oi.customer_id,
sum( oi.total_amount - oi.paid_amount ) as OIBalance
from
{CI}offline_invoice oi
where
oi.customer_id = ?
and oi.status not like 'paid%'
group by
i.customer_ID ) as OIInvoces
on CurInvoices.Customer_ID = OIInvoices.customer_ID