DBI202Xuất hiện trong 1 đề thi
Assume that all tables, columns are ready, and each customer can place one or more orders. How can you retrieve all customers who have not made any purchases? (choose two options)
Các lựa chọn
ASELECT c.CustomerID, c.CustomerName, c.Email, c.CreatedDate
FROM dbo.Customers AS c
WHERE NOT EXISTS (
SELECT 1
FROM dbo.Orders AS o
WHERE o.CustomerID = c.CustomerID
);
BSELECT c.CustomerID, c.CustomerName, c.Email, c.CreatedDate
FROM dbo.Customers AS c LEFT JOIN dbo.Orders AS o
ON c.CustomerID = o.CustomerID
WHERE o.OrderID IS NULL;
CSELECT c.CustomerID, c.CustomerName, c.Email, c.CreatedDate
FROM dbo.Customers AS c INNER JOIN dbo.Orders AS o
ON c.CustomerID = o.CustomerID
WHERE o.OrderID IS NULL;
DSELECT c.CustomerID, c.CustomerName, c.Email, c.CreatedDate
FROM dbo.Customers AS c RIGHT JOIN dbo.Orders AS o
ON c.CustomerID = o.CustomerID
WHERE o.OrderID IS NULL;