SQL Server 2012 合并 OUTER APPLY 相关的记录 table

Question

我有一个包含客户详细信息的 Table "Customers" 和 Table "CALLS" 我存储每个电话的结果的地方

当我需要获取必须呼叫的客户列表时，我使用此查询

SELECT *
FROM (
    SELECT TOP (50) S.ID,S.URL,S.Phone,S.Email
    FROM dbo.Customers AS S
    WHERE URL is not null and City like 'Berl%'
    ORDER BY S.ID 
    ) AS S

OUTER APPLY (
SELECT TOP (3) I.CalledOn, I.Answer
FROM dbo.Calls AS I
WHERE S.URL = I.URL
ORDER BY I.CalledOn DESC
) AS I;

我在哪里可以得到城市中所有客户的名单以及最后 3 个答案。

但这 returns 每个客户最多 3 条记录，而我只有一条并将CalledOn和Answer的3个值汇总到同一条记录中

更清楚一点：现在：

+-----------+---------------+-------------+------------------+
|Customer 1 |  555-333 333  | 02-10-17    | Call Tomorrow    |
+-----------+---------------+-------------+------------------+
|Customer 2 |  555-444 333  | 02-10-17    | Call Tomorrow    |
+-----------+---------------+-------------+------------------+
|Customer 1 |  555-333 333  | 02-11-17    | Call Tomorrow    |
+-----------+---------------+-------------+------------------+
|Customer 1 |  555-333 333  | 02-12-17    | Stop Calling     |
+-----------+---------------+-------------+------------------+

预计

+-----------+---------------+--------------------------------+
|Customer 1 |  555-333 333  | 02-12-17 : Call Stop Calling   |
|           |               | 02-11-17 : Call Tomorrow       |
|           |               | 02-10-17 : Call Tomorrow       |
+-----------+---------------+-------------+------------------+
|Customer 2 |  555-444 333  | 02-10-17    | Call Tomorrow    |
+-----------+---------------+-------------+------------------+

目前我正在使用服务器端逻辑实现此目的，但我确信使用 TSQL 可以更轻松、更好地完成它

可以指点方向吗？

谢谢

Answer 1

对于 SQL-Server 2012

SELECT TOP (50) S.ID, S.URL, S.Phone, S.Email,
           STUFF((SELECT CHAR(10) + concat (I.CalledOn, ' ', I.Answer)
                  FROM dbo.Calls AS I
                  WHERE S.URL = I.URL
                  ORDER BY I.CalledOn DESC
                  FOR XML PATH('')
                ), 1, 1, '') AS CallAnswer
FROM dbo.Customers AS S
WHERE URL is not null and City like 'Berl%'
ORDER BY S.ID

v下一个：

SELECT TOP (50) S.ID, S.URL, S.Phone, S.Email,
           (SELECT TOP (3) STRING_AGG(CONCAT(I.CalledOn, ' ', I.Answer), CHAR(13))
            FROM dbo.Calls AS I
            WHERE S.URL = I.URL
            ORDER BY I.CalledOn DESC
           ) AS CallAnswer
FROM dbo.Customers AS S
WHERE URL is not null and City like 'Berl%'
ORDER BY S.ID

在这里查看：http://rextester.com/HSIEL20631

SQL Server 2012 合并 OUTER APPLY 相关的记录 table

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