Tsql T-SQL:是否在记录列表中显示值

我有一张客户、订单和物品的表格。我想写一份报告，每行有一个客户（在这个例子中，我假设每个客户有一个订单），以及是否订购了某些物品

客户：

id firstName

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一切都很好，但您需要在join子句中过滤外部联接，否则将外部联接变成内部联接。我已将

Name

列添加到项目中，但它可能应该是

ProductID

，它是带有ProductName的产品表的外键

SELECT c.firstName, i_apple.Name Apple, i_banana.Name Banana
FROM customers
LEFT JOIN orders o 
  ON c.id = o.customers_id
LEFT JOIN items i_apple 
  ON o.id = i_apple.orders_id
 AND i_apple.Name = 'apple'
LEFT JOIN items i_banana 
  ON o.id = i_banana.orders_id
 AND i_banana.Name = 'banana'

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如果添加

sql

和

sqlserver版本

标记，您将获得更多关注。 id orders_id

SELECT c.firstName, i_apple, i_banana
FROM customers
LEFT JOIN orders o ON c.id = o.customers_id
LEFT JOIN items i_apple ON o.id = i_apple.orders_id
LEFT JOIN items i_banana ON o.id = i_banana.orders_id
WHERE i_apple = 'apple' AND i_banana = 'banana'

SELECT c.firstName, i_apple.Name Apple, i_banana.Name Banana
FROM customers
LEFT JOIN orders o 
  ON c.id = o.customers_id
LEFT JOIN items i_apple 
  ON o.id = i_apple.orders_id
 AND i_apple.Name = 'apple'
LEFT JOIN items i_banana 
  ON o.id = i_banana.orders_id
 AND i_banana.Name = 'banana'