I have two tables, orders and customers, and I am trying to return the customerID and name of customers with no orders.
我有两个表，订单和客户，我试图返回没有订单的客户ID和客户名称。
customers
customerID: integer
name: string
orders
orderID: integer
itemID: integer
customerID: integer
date: date
What I currently have is not returning any results:
我目前所拥有的不会返回任何结果：
SELECT customers.customerID, customers.fName, orders.date
FROM orders INNER JOIN customers
ON orders.customerID = customers.customerID
GROUP BY orders.customerID
HAVING COUNT(*) = 0
1 个解决方案
#1
1
You need a LEFT OUTER JOIN to accomplish this:
你需要一个LEFT OUTER JOIN来完成这个：
SELECT customers.customerID, customers.fName
FROM customers LEFT OUTER JOIN orders on customers.customerID = orders.customerID
WHERE orders.customerID IS NULL
#1
1
You need a LEFT OUTER JOIN to accomplish this:
你需要一个LEFT OUTER JOIN来完成这个：
SELECT customers.customerID, customers.fName
FROM customers LEFT OUTER JOIN orders on customers.customerID = orders.customerID
WHERE orders.customerID IS NULL