删除 ... 输出计数（已删除。*）

Question

我想知道在某个 DELETE 操作中删除了多少行。

我拿了 the Microsoft example B 也就是

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

并尝试将其修改为 return 只有 count 条已删除的记录：

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

但这抛出

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

所以我尝试了

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

抛出

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

我错过了什么？

Answer 1

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

DECLARE @t TABLE(id int)

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

SELECT COUNT(*) FROM @t

Answer 2

之后统计记录如何？

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

SELECT COUNT(*)
FROM @DELETEDIDS;

或者，仅 运行 查询并使用 @@ROWCOUNT。

Answer 3

只需 运行 您的查询并获取修改后的行

DELETE 
FROM datacache 
WHERE userId=@id

SELECT @@ROWCOUNT