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CREATE TABLE customers
(`aleID` int, `CustomerID` int, `SaleRegion` varchar(6))
;
INSERT INTO customers
(`aleID`, `CustomerID`, `SaleRegion`)
VALUES
(1, 7, 'CITY A'),
(2, 10, NULL),
(3, 10, NULL),
(4, 7, 'CITY A'),
(5, 10, 'CITY B')
;
Records: 5 Duplicates: 0 Warnings: 0
SELECT
`CustomerID`, FIRST_VALUE(`SaleRegion`) OVER( PARTITION BY `CustomerID` ORDER BY `SaleRegion` DESC
) as SaleRegion
FROM customers
| CustomerID | SaleRegion |
|---|---|
| 7 | CITY A |
| 7 | CITY A |
| 10 | CITY B |
| 10 | CITY B |
| 10 | CITY B |