Select keyids already refunded or yet to refund

[kyath_sas]

Hi could any one help on below
Input dataset :
Keyid Coupon Month Price
1 12b 201701 100
1 12c 201702 0
1 12b 201703 -100
2 14c 201702 0
2 14b 201703 200
3 15b 201705 100
3 15c 201706 0
3 15b 201707 -100
3 15b 201708 200
4 16b 201705 250
4 16c 201706 0



Output below like this

1 12b 201701 100
1 12c 201702 0
1 12b 201703 -100
3 15b 201705 100
3 15c 201706 0
3 15b 201707 -100
4 16b 201705 250
4 16c 201706 0
Which are the keyid have coupon ends with’c’ then paid amount will be refund

[PeterClemmensen]

Can you be a little more specific in your requirements?

For example, why is Keyid=2 left out of the output data but Keyid=4 is in there?

[kyath_sas]

Keyid 2 coupon came 201702 actual paid month 201703 we dont need this keyid because refund is not possible in this situation . Select keyid paid month prior than coupon month