amazon redshift - Split a payment over multiple invoices using SQL

Question

Source data in table Inv-Payments:

Date	Customer	Inv ID	Inv Amt	Pmt ID	Pmt Amt
Jan 1	ABC	Inv-1	500	NULL	NULL
Jan 2	ABC	Inv-2	1000	NULL	NULL
Jan 3	ABC	NULL	NULL	PMT-1	250
Jan 4	ABC	NULL	NULL	PMT-2	500
Jan 5	ABC	NULL	NULL	PMT-3	750

question from:https://stackoverflow.com/questions/66057080/split-a-payment-over-multiple-invoices-using-sql

Answer 1

I believe the logic here is to duplicate every row to have a second invoice.

Use the SQL UNION or UNION ALL function and add your logic for Pmt ID, Pmt Amt, inv_balance.