请教修改SQL

Question

isnull函数 isnull(子段名,'') 或者 isnull(子段名,0)

Answer 1

SELECT isnull(Employees.Name,''), Orders.Product
FROM Employees
LEFT JOIN Orders
ON Employees.ID = Orders.ID

Answer 2

SELECT isnull(Employees.Name,'') as Name, isnull(Orders.Product,0) as Product
FROM Employees
LEFT JOIN Orders
ON Employees.ID = Orders.ID

Answer 3

SELECT isnull(Employees.Name,'') as Name, isnull(Orders.Product,0) as Product
FROM Employees
LEFT JOIN Orders
ON Employees.ID = Orders.ID