sql - SQL Server SELECT STUFF 返回不正确的值

Question

我过去使用过 STUFF，没有任何问题，但这个有点不同。也许是由于表结构。如果有人想看一下，我已经设置了一些不错的测试脚本。任何输入表示赞赏。

DECLARE @DetailTbl TABLE(DetailID INT IDENTITY(1,1) NOT NULL, Roll VARCHAR(6))
INSERT INTO @DetailTbl (Roll) VALUES ('ABC')
INSERT INTO @DetailTbl (Roll) VALUES ('DEF')
INSERT INTO @DetailTbl (Roll) VALUES ('JKL')
INSERT INTO @DetailTbl (Roll) VALUES ('MNO')

DECLARE @RunTbl TABLE(ID INT IDENTITY(1,1) NOT NULL, Run VARCHAR(6))
INSERT INTO @RunTbl (Run) VALUES ('X12')
INSERT INTO @RunTbl (Run) VALUES ('Y34')
INSERT INTO @RunTbl (Run) VALUES ('Z56')

DECLARE @RunRollRef TABLE(ID INT IDENTITY(1,1) NOT NULL, RunID INT, DetailID INT)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (1, 1)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (1, 2)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (1, 3)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (2, 4)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (2, 1)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (3, 2)
INSERT INTO @RunRollRef (RunID, DetailID) VALUES (3, 3)

SELECT rt.ID,

(SELECT
STUFF((SELECT dt.Roll + ','
FROM @DetailTbl dt
INNER JOIN @RunRollRef ref ON ref.DetailID = dt.DetailID
WHERE dt.DetailID = r.DetailID
FOR XML PATH(''), TYPE).value('.','VARCHAR(MAX)'), 1, 0, '')) 
AS Rolls

FROM @RunTbl rt
INNER JOIN @RunRollRef r ON r.RunID = rt.ID

--Expected Output
--1 ABC,DEF,JKL,
--2 MNO,ABC,
--3 DEF,JKL,

标签： sqlsql-server

Answer 1

我会使用APPLY：

select rt.ID, stuff(tt.Rolls, 1, 1, '') as Rolls
from @RunTbl rt outer apply
     ( select ', '+dt.Roll
       from @RunRollRef rf inner join
            @DetailTbl dt
            on dt.DetailID = rf.DetailID
       where rf.RunID = rt.ID
       for xml path('')
     ) tt(Rolls);

外部select有不必要JOIN的 s，这实际上是不需要的。

您需要引用ref.RunID = rt.ID而不是dt.DetailID = r.DetailID在子查询中。