从表中获取以逗号分隔的一组值，其中另一个表上的另一个参考值出现两次（或多次）

Question

假设 SQL Server 2014 中的数据库设置如下：

DECLARE @MATERIAL TABLE (ID int, CODE varchar(30));

INSERT @MATERIAL (ID, CODE) VALUES
(1, 'D3033MBBY'),
(2, 'D3033MBTY'),
(3, '011130-01'),
(4, '011130-04C'),
(5, '021002'),
(6, '021017-B'),
(7, '021134-01'),
(8, '021135-01'),
(9, '021955-01'),
(10, '3LS91101-550'),
(11, 'D3049MBRB'),
(12, 'EF0118'),
(13, 'FV8130'),
(14, 'FY7009'),
(15, 'H05802'),
(16, 'D3033MRTE');

DECLARE @SUBSTITUTE TABLE (ID int, ITEID int, SUBSTITUTECODE varchar(100));

INSERT @SUBSTITUTE (ID, ITEID, SUBSTITUTECODE) VALUES
(5232, 1, '191045762418'),
(5442, 2, '191045762418'),
(6435, 3, '5206432380030'),
(6573, 4, '5206432380030'),
(6582, 5, '5206432357131'),
(6683, 6, '5206432369486'),
(7332, 7, '5206432380610'),
(7482, 8, '5206432380818'),
(7721, 9, '5206432346029'),
(7831, 10, '5205172116350'),
(8034, 11, '191045480992'),
(8184, 12, '4061622759543'),
(8284, 13, '4062058577497'),
(8573, 14, '4064039588089'),
(9438, 15, '4064048672519'),
(9746, 16, '191045762418');

SELECT sub.SUBSTITUTECODE
FROM @SUBSTITUTE AS sub
INNER JOIN @MATERIAL AS prod ON prod.ID = sub.ITEID
GROUP BY sub.SUBSTITUTECODE
HAVING COUNT(sub.SUBSTITUTECODE) > 1;

我想创建一个会产生以下结果集的查询：

代码	替代代码
D3033MBBY,D3033MBTY,D3033MRTE	191045762418
011130-01,011130-04C	5206432380030

换句话说，我想获得一组以逗号分隔的CODEs，其中表中的记录@MATERIAL有重复引用SUBSTITUTECODE@SUBSTITUTE

我可以通过以下查询间接找到CODE与这些重复的 s 相对应的 s ：SUBSTITUTECODE

SELECT prod.CODE, sub.SUBSTITUTECODE
FROM @SUBSTITUTE AS sub
INNER JOIN @MATERIAL AS prod ON prod.ID = sub.ITEID
WHERE sub.SUBSTITUTECODE IN (SELECT sub.SUBSTITUTECODE
    FROM @SUBSTITUTE AS sub
    INNER JOIN @MATERIAL AS prod ON prod.ID = sub.ITEID
    GROUP BY sub.SUBSTITUTECODE
    HAVING COUNT(sub.SUBSTITUTECODE) > 1)

上述案例的工作小提琴可以在这里找到。

请注意，此场景的完整案例在 SQL Server 2014 上运行。

TIA

Answer 1

很好的开始小提琴，谢谢！如果我们只是将您已有的内容放入 CTE 中，我们可以围绕它编写一个标准字符串聚合：

;WITH subs AS 
(
  SELECT prod.CODE, sub.SUBSTITUTECODE
  FROM @SUBSTITUTE AS sub
  INNER JOIN @MATERIAL AS prod ON prod.ID = sub.ITEID
  WHERE sub.SUBSTITUTECODE IN (SELECT sub.SUBSTITUTECODE
    FROM @SUBSTITUTE AS sub
    INNER JOIN @MATERIAL AS prod ON prod.ID = sub.ITEID
    GROUP BY sub.SUBSTITUTECODE
    HAVING COUNT(sub.SUBSTITUTECODE) > 1)
)
SELECT CODES = STUFF((SELECT ',' + CODE 
  FROM subs AS s2 WHERE s2.SUBSTITUTECODE = subs.SUBSTITUTECODE
  FOR XML PATH(''), TYPE).value(N'./text()[1]', N'nvarchar(max)'),1,1,''),
    SUBSTITUTECODE FROM subs
  GROUP BY SUBSTITUTECODE;

• 示例db<>fiddle

但我们可以稍微简化这段代码，最重要的是避免两次引用这两个表，如下所示：

;WITH subs AS
(
  SELECT s.ITEID, s.SUBSTITUTECODE, m.CODE, 
    c = COUNT(*) OVER (PARTITION BY s.SUBSTITUTECODE)
  FROM @SUBSTITUTE AS s
  INNER JOIN @MATERIAL AS m
  ON m.ID = s.ITEID
)
SELECT CODES = STUFF((SELECT ',' + CODE
  FROM subs AS s2 WHERE s2.SUBSTITUTECODE = subs.SUBSTITUTECODE
  FOR XML PATH(''), TYPE).value(N'./text()[1]', N'nvarchar(max)'),1,1,''),
    SUBSTITUTECODE
  FROM subs 
  WHERE c > 1 
  GROUP BY SUBSTITUTECODE;

• 示例db<>fiddle

请注意，在更现代的 SQL Server 版本（2017+）上，STRING_AGG()这使得这变得更容易：

SELECT CODES = STRING_AGG(m.CODE, ','), s.SUBSTITUTECODE
  FROM @SUBSTITUTE AS s
  INNER JOIN @MATERIAL AS m
  ON m.ID = s.ITEID
  GROUP BY s.SUBSTITUTECODE
  HAVING COUNT(*) > 1;

• 示例db<>fiddle