Question

如果我这样做，那不正确吗？

ALTER FUNCTION [dbo].[fn_ItemInventory] (@CustomerId)
RETURNS TABLE AS
   SELECT * FROM Inventory WHERE Warehouse = fn_GetWarehouse(@CustomerId)

理想情况下我想这样做，但ITVF不允许这样做：

ALTER FUNCTION [dbo].[fn_ItemInventory] (@CustomerId)
RETURNS TABLE AS
   SET @Warehouse = fn_GetWarehouse(@CustomerId)
   SELECT * FROM Inventory WHERE Warehouse = @Warehouse

我不想使用MSTVF，因为查询优化器无法对其进行优化。最后我使用了这个解决方法：

ALTER FUNCTION [dbo].[fn_ItemInventory] (@CustomerId)
RETURNS TABLE AS
   SELECT * FROM fn_Inventory(fn_GetWarehouse(@CustomerId))

fn_Inventory接受@Warehouse作为参数，并使用参数查询Inventory表，从而避免此问题。处理这种情况是否没有标准模式？

Answer 1

你忘记了回复陈述。

ALTER FUNCTION [dbo].[fn_ItemInventory] (@CustomerId)
RETURNS TABLE AS
   RETURN SELECT * FROM Inventory WHERE Warehouse = fn_GetWarehouse(@CustomerId)

或者，您需要begin和end来标记代码块，而不仅仅是单个return语句，所以：

ALTER FUNCTION [dbo].[fn_ItemInventory] (@CustomerId)
RETURNS @tableName TABLE (<TableDefinition>) AS
BEGIN
   SET @Warehouse = fn_GetWarehouse(@CustomerId)
   INSERT INTO @TableName SELECT * FROM Inventory WHERE Warehouse = @Warehouse
   RETURN
END

Answer 2

我会尝试制作fn_GetWarehouse和内联表值函数并加入它。

ALTER FUNCTION [dbo].[fn_ItemInventory] (@CustomerId)
RETURNS TABLE AS
RETURN (
    SELECT 
         _Inventory.*
    FROM Inventory _Inventory
    join fn_GetWarehouse(@CustomerId) _Warehouse
        on _Warehouse.warehouse = _Inventory.Warehouse
)

内联表值函数内的Where子句中的函数

2 个答案: