DELETE ... OUTPUT COUNT（DELETED。*）

Question

我想知道在某个DELETE操作中删除了多少行。

我拿了微软的例子B

DELETE Sales.ShoppingCartItem
OUTPUT DELETED.* 
WHERE ShoppingCartID = 20621;

并尝试修改它以仅返回已删除记录的count ：

DELETE FROM datacache 
OUTPUT COUNT(DELETED.*)
WHERE userId=@id

但这引发了

ExceptionMessage: "Incorrect syntax near '*'."
ExceptionType: "System.Data.SqlClient.SqlException"
Message: "Error"

所以我试过了

DELETE FROM datacache 
OUTPUT COUNT(DELETED)
WHERE userId=@id

哪个扔了

ExceptionMessage: "Invalid column name 'DELETED'."
ExceptionType: "System.Data.SqlClient.SqlException"
Message: "Error"

我错过了什么？

Answer 1

只需运行您的查询并获取修改后的行

DELETE 
FROM datacache 
WHERE userId=@id

SELECT @@ROWCOUNT

Answer 2

您不能在OUTPUT子句中使用聚合。 您可以将任何列输出到表变量中，并从那里开始计数：

DECLARE @t TABLE(id int)

DELETE FROM Sales.ShoppingCartItem
OUTPUT Deleted.ShoppingCartID INTO @t
WHERE ShoppingCartID = 20621;

SELECT COUNT(*) FROM @t

Answer 3

之后如何计算记录？

DELETE Sales.ShoppingCartItem
OUTPUT DELETED.ID INTO @DELETEDIDS
WHERE ShoppingCartID = 20621;

SELECT COUNT(*)
FROM @DELETEDIDS;

或者，只需运行查询并使用@@ROWCOUNT 。