Question

The following query is constantly timing out, is there a less overhead way to achieve the same function ?

UPDATE Invoices SET ispaid = 0 
WHERE Invoice_number IN (SELECT invoice_number
    FROM payment_allocation
    WHERE transactionID=305)

What I’m doing is unallocating invoices from a transaction, there can be up to 30+ records returned but it stops the database dead everytime I try to run it

Answer 1

USE JOIN instead of subquery it will improve the performance.

Create index on Invoice_number column in both table if you haven’t created.

Try this:

UPDATE Invoices i 
INNER JOIN payment_allocation pa ON i.Invoice_number = pa.invoice_number 
SET i.ispaid = 0 
WHERE pa.transactionID = 305;