如何在Microsoft SQL Server Management Studio中将多行合并为一行，用逗号分隔

Question

我正试图根据匹配的user_id将以下id连接到一行中。

当前代码

SELECT
A.USER_ID,
B.POINT_ID
FROM DATABASE1 AS A
LEFT JOIN DATABASE2 as b on a.SSCL_ID = b.SEC_ID
WHERE
RECORD_STATUS in ('2','5')
and USER_STATUS = '1'

我尝试了以下代码：

SELECT c.USER_ID,
STUFF((SELECT DISTINCT ',' + cast(POINT_ID as varchar(10))
FROM DATABASE1 A
LEFT JOIN DATABASE2 as b on a.SSCL_ID = b.SEC_ID
FOR XML PATH ('')), 1, 1, '') 
from DATABASE1 c
WHERE
RECORD_STATUS in ('2','5')
and USER_STATUS = '1'
group by c.USER_ID

Answer 1

请尝试以下解决方案。

SQL

-- DDL and sample data population, start
DECLARE @tbl TABLE (ID INT IDENTITY PRIMARY KEY, [USER_ID] VARCHAR(10), POINT_ID INT);
INSERT INTO @tbl ([USER_ID], POINT_ID) VALUES
('T0070',1 ),
('T0070',2 ),
('T0070',3 ),
('T1234',10),
('T1234',11),
('T1234',12),
('T1234',13),
('T1234',14);
-- DDL and sample data population, end
DECLARE @separator CHAR(1) = ',';
SELECT p.[USER_ID], 
STUFF((SELECT @separator + CAST(POINT_ID AS VARCHAR(30)) AS [text()]
FROM @tbl AS c
WHERE c.[USER_ID] = p.[USER_ID] 
ORDER BY c.POINT_ID
FOR XML PATH(''), TYPE).value('text()[1]','NVARCHAR(MAX)'), 1, 1, NULL) AS POINT_ID_LIST
FROM @tbl AS p
GROUP BY p.USER_ID;

输出

+---------+----------------+
| USER_ID | POINT_ID_LIST  |
+---------+----------------+
| T0070   |          1,2,3 |
| T1234   | 10,11,12,13,14 |
+---------+----------------+

Answer 2

内部FOR XML PATH聚合必须是外部USER_ID的函数

with cte as(
SELECT
A.USER_ID,
B.POINT_ID
FROM DATABASE1 AS A
LEFT JOIN DATABASE2 as b on a.SSCL_ID = b.SEC_ID
WHERE
RECORD_STATUS in ('2','5')
and USER_STATUS = '1'
)
SELECT c1.USER_ID,
STUFF((SELECT ',' + cast(POINT_ID as varchar(10))
FROM cte c2
WHERE c2.USER_ID = c1.USER_ID
FOR XML PATH ('')), 1, 1, '')
FROM cte c1

Answer 3

你能使用string_agg()吗？

SELECT A.USER_ID, STRING_AGG(B.POINT_ID, ',')
FROM DATABASE1 A LEFT JOIN
DATABASE2 b 
ON a.SSCL_ID = b.SEC_ID
WHERE RECORD_STATUS in ('2', '5') AND
USER_STATUS = '1'
GROUP BY A.USER_ID;