二、有一資料表 Sales(OrderID, CustID, Amount, ODate) 。請回答下列問題:
(二)下列 SQL 陳述式的作用為何?SELECT CustID, SUM(Amount)AS TotalAmt FROM Sales WHERE ODate >= DATE '2025-01-01' AND ODate < DATE '2025-02-01' GROUP BY CustID ORDER BY TotalAmt DESC;