轉換存儲過程，表值查詢

Question

我有這個程序

ALTER PROCEDURE [dbo].GetHerdByUserProc(@user int) 
As 
    begin 
     Declare 
      @GroupId uniqueidentifier, 
      @UserTrade bit 

     Set @GroupId = (select tbUser.group_id from tbUser where Userid = @user) 
     Set @UserTrade = (select tbUser.isTrade from tbUser where Userid = @user) 
     if @GroupId IS NOT NULL and @UserTrade = '1' 
     Begin 
      select HerdId from tbUserHerds where tbUserHerds.UserId in (select Userid from tbUser where tbUser.Group_Id = @GroupId) 
      return; 
     END 
     If @GroupId IS NOT NULL 
     Begin 
      select HerdId from tbUserHerds where tbUserHerds.UserId = @user 
      return; 
     End 
     return; 
    End 

它正確地返回一個列表，除了我還想運行，返回和列表上的查詢，據我所知，我不能寫一個查詢，如

Select * from GetHerdByUserProc 80 

所以我正在尋找最好的方式將其轉換爲表值查詢。

我已經改變了ALTER說'Create Function x(@user int) Returns Table As'

但是，這並不縫工作，它開始向我大聲尖叫錯誤。

任何想法？數據庫服務器是MSSQL2008

Answer 1

根據你的語法，我要承擔的SQL Server現在。

從BOL的語法內聯函數應該是...

--Transact-SQL Inline Table-Valued Function Syntax 
CREATE FUNCTION [ schema_name. ] function_name 
([ { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type 
    [ = default ] [ READONLY ] } 
    [ ,...n ] 
    ] 
) 
RETURNS TABLE 
    [ WITH <function_option> [ ,...n ] ] 
    [ AS ] 
    RETURN [ (] select_stmt [) ] 
[ ; ] 

使用此格式，您不能使用SET, DECLARE, IF, etc。你可以使用的只是一個SQL語句。 [如果你需要使用程序流程，看多語句表值函數。]

這是一個獨立的主題，但內聯表值函數有超過他們的多語句equivilents 許多性能效率。幾乎總是，如果你可以做到內聯，你應該這樣做。

碰巧，您可以在不使用IF語句的情況下編寫邏輯，只使用一條SQL語句。這給出了以下內嵌表值函數...

CREATE FUNCTION [dbo].GetHerdByUserProc(@user int) 
RETURNS TABLE 
RETURN 
    SELECT 
    herd.HerdID 
    FROM 
    tbUser   AS user 
    INNER JOIN 
    tbUser   AS group 
     ON group.group_id = user.group_id 
    INNER JOIN 
    tbUserHerds  AS herd 
     ON herd.UserID = group.UserID 
    WHERE 
     user.userID = @userID 
    AND user.isTrade = 1 
    AND user.group_id IS NOT NULL 

    UNION ALL 

    SELECT 
    herd.HerdID 
    FROM 
    tbUser   AS user 
    INNER JOIN 
    tbUserHerds  AS herd 
     ON herd.UserID = user.UserID 
    WHERE 
     user.userID = @userID 
    AND user.isTrade <> 1 
    AND user.group_id IS NOT NULL 

的UNION ALL與WHERE條款有效地做你的IF報表合併你。 （請注意，如果user.isTrade可以NULL，您需要更改user.isTrade <> 1到更多的東西一樣ISNULL(user.isTrade, 0) <> 1）

潛在的，你甚至可以簡化這個到一個單一的查詢，但我會進行測試，看看如果它實際上任何更有效或不...

RETURN 
    SELECT 
    herd.HerdID 
    FROM 
    tbUser   AS user 
    INNER JOIN 
    tbUser   AS group 
     ON (group.group_id = user.group_id AND user.isTrade = 1) 
     OR (group.user_id = user.userID) 
    INNER JOIN 
    tbUserHerds  AS herd 
     ON herd.UserID = group.UserID 
    WHERE 
    user.userID = @userID 

• 如果group_id爲NULL，先加入絕不會得逞的。
• 那麼兩個IF塊由OR模擬。

Answer 2

您可以在PROC的結果存儲在一個臨時表：

INSERT INTO #temptbl EXEC [dbo].GetHerdByUserProc(80) 

Answer 3

您需要定義表的結構定義，然後插入值到申報表變量...

create function x 
(
    @user int 
) 
returns @t 
( 
    herdid int 
) 
as 
begin 
    insert @t (herdid) 
    select HerdId from tbUserHerds where tbUserHerds.UserId = @user 
    -- or whatever... 
    return 
end 

見http://msdn.microsoft.com/en-us/library/ms191165(v=sql.105).aspx

Answer 4

您可以使用CASE語句簡單地寫SQL查詢。 CASE語句是處理條件查詢的最簡單方法。

Declare @GroupId uniqueidentifier,@UserTrade bit 

select HerdId 
from tbUserHerds 
where 
1 = CASE 
    WHEN (select tbUser.group_id from tbUser where Userid = @user) IS NOT NULL 
    THEN 
     CASE 
      WHEN tbUserHerds.UserId = @user THEN 1 
      ELSE 0 
     END 

    WHEN 
      (select tbUser.group_id from tbUser where Userid = @user) IS NOT NULL  and   (select tbUser.isTrade from tbUser where Userid = @user) = '1' 
    THEN 
     CASE 
      WHEN tbUserHerds.UserId in (select Userid from tbUser  where tbUser.Group_Id = (select tbUser.group_id from tbUser where Userid = @user)) THEN 1 
      ELSE 0 
     END 
END