在 SQL Server 中跨多行分别连接多个列

Question

我需要在 SQL Server 中连接两个表的多行数据中分别连接两列。

例如，我有一个“关联”表和“市场”表，如下所示”

Association:

user_id |  role_id  | market_id
-------------------------------
1       |     a     |     1
1       |     a     |     2
2       |     c     |     3
2       |     c     |     4
2       |     c     |     5

Market:

market_id | market_name
-----------------------
1         | Arizona
2         | Utah
3         | Indiana
4         | Illinois
5         | Kentucky

我需要将关联表中的 market_id 连接成每个用户 ID 的单个值，并从市场表中引入连接的市场名称，我想要的输出如下所示：

user_id |  role_id  |  market_ids   | market_names
--------------------------------------------------
1       |     a     |     1,2       | Arizona,Utah
2       |     c     |    3,4,5      | Indiana,Illinois,Kentucky

现在，我能够成功连接市场 ID，但仍然使用以下 SQL 为每个市场获得多行数据：

SELECT DISTINCT
    a.user_id,
    a.role_id,
    SUBSTRING(
        (
            SELECT DISTINCT ', ' + market_id  AS [text()]
            FROM Association aa
            WHERE a.user_id = aa.user_id
            FOR XML PATH ('')
        ), 2, 1000) [market_ids],
        SUBSTRING(
        (
            SELECT DISTINCT ', ' + market_name  AS [text()]
            FROM Market bb
            WHERE a.market_id = bb.market_id
            FOR XML PATH ('')
        ), 2, 1000) [Market Name]
FROM
    Association a
    INNER JOIN
    Market b
        ON a.market_id = d.market_id

关于如何实现第二个串联有什么想法吗？

Answer 1

具有 Row_Number() 的 CTE 来保持呈现顺序应该可以解决问题

例子

;with cte as (
    Select A.*
          ,B.Market_Name
          ,RN = Row_Number() over (Partition By user_id,role_id order by a.market_id)
     From   Association A
     Join   Market B on A.market_id=B.market_id
)
Select Distinct
       user_id
      ,role_id
      ,market_ids   = stuff((Select concat(',',market_id  ) From cte Where user_id=A.user_id and role_id=A.role_id Order By RN For XML Path ('')),1,1,'')
      ,market_names = stuff((Select concat(',',market_name) From cte Where user_id=A.user_id and role_id=A.role_id Order By RN For XML Path ('')),1,1,'')
 From  cte A

退货

user_id role_id market_ids  market_names
1       a       1,2         Arizona,Utah
2       c       3,4,5       Indiana,Illinois,Kentucky