TSQL Raws into Columns按另一列分组

Question

我想从开始表中获取所需的表，并另外按另一列（日期）分组。

在这里，我有什么建议吗？

Answer 1

尝试一下：

DECLARE @DataSource TABLE
(
    [Case] INT
   ,[ErrorCode] CHAR(1)
   ,[Date] DATE
);

INSERT INTO @DataSource ([Case], [ErrorCode], [Date])
VALUES (1, 'A', '2018-01-25')
      ,(1, 'B', '2018-01-15')
      ,(1, 'C', '2018-01-15')
      ,(1, 'A', '2018-01-15')
      ,(1, 'D', '2018-01-15')
      ,(1, 'A', '2018-01-15')
      --
      ,(2, 'D', '2018-01-26')
      ,(2, 'A', '2018-01-26')
      ,(2, 'D', '2018-01-25')
      ,(2, 'D', '2018-01-24')
      ,(2, 'C', '2018-01-24');

SELECT DISTINCT DS.[Case]
               ,DS.[Date]
               ,Errors.[ErrorCode]
FROM @DataSource DS
CROSS APPLY
(
    SELECT STUFF
    (
        (
            SELECT ' / ' + [ErrorCode]
            FROM @DataSource DSI
            WHERE DS.[Case] = DSI.[Case]
                AND DS.[Date] = DSI.[Date]
            FOR XML PATH(''), TYPE
        ).value('.', 'VARCHAR(MAX)')
        ,1
        ,3
        ,''
    )
) Errors ([ErrorCode])
ORDER BY [Case]
        ,[Date] DESC;

Answer 2

您可以使用STRING_AGG

请尝试以下操作：

SELECT [Case], [Date], STRING_AGG (ErrorCode, '/') AS ErrorCode 
FROM Table1
Group by [Case], [Date]; 

Answer 3

请尝试这个。

SELECT distinct [Case], [Date],STUFF(
(SELECT '/' + ErrorCode
FROM Table1 as a
where a.[Case] = b.[Case] and  a.Date  = b.Date
ORDER BY ErrorCode
FOR XML PATH('')),1,1,'') AS ErrorCode
FROM Table1 as b

Answer 4

尝试一下，

 select DISTINCT [Case],[Date],
    STUFF((Select '/'+ErrorCode
           from Table1 T1
           where T1.[Case]=T2.[Case]
           And  T1.[Date] =T2.[Date]
           FOR XML PATH('')),1,1,'') As ErrorCode 
 from  Table1 T2
    ORDER BY [Case],[Date] DESC;

Answer 5

在这种情况下，非聚集索引是成功的关键。现在需要3秒钟才能处理80k原始数据！

比我预期的要好：）