將表作爲參數並執行連接的表值函數

Question

我使用SQL Server 2016. 我想編寫一個函數，它將一個表作爲參數，然後在該表上執行與另一個表的連接。 我宣佈以下類型：

CREATE TYPE WorklistTable AS TABLE (WorklistId int NOT NULL) 

然後我用它了很多基​​於某些條件做選擇功能

CREATE FUNCTION [dbo].[fnGetSomeData] (
@WorklistIds WorklistTable readonly 
) 
RETURNS TABLE 
    AS RETURN 
    ( 
    select WorklistId, wlu.UserId 
    from @WorklistIds 
    join [dbo].[WorklistUser] wlu on wlu.WorklistId = @WorklistIds.worklistId 
    -- the rest is omitted 
); 

我收到以下錯誤：

Must declare the scalar variable "@WorklistIds".

我試圖聲明變量，但出現錯誤：

The variable name '@WorklistIds' has already been declared. Variable names must be unique within a query batch or stored procedure.

Answer 1

你應該使用別名，當你正在表變量。

CREATE FUNCTION [dbo].[fnGetSomeData] (
@WorklistIds WorklistTable readonly 
) 
RETURNS TABLE 
    AS RETURN 
    ( 
    select WorklistId, wlu.UserId 
    from @WorklistIds t 
    join [dbo].[WorklistUser] wlu on wlu.WorklistId = t.worklistId 
    -- the rest is omitted 
); 

Answer 2

在引用表變量中的列時，不能直接使用@Table名稱。您可能需要別名表或在方括號包起來：

select WorklistId, wlu.UserId 
from @WorklistIds As W 
join [dbo].[WorklistUser] wlu on wlu.WorklistId = W.worklistId 

或者

select WorklistId, wlu.UserId 
from @WorklistIds 
join [dbo].[WorklistUser] wlu on wlu.WorklistId = [@WorklistIds].worklistId