按列和多行分组为 One Row 多列

Question

请帮帮我：

我想按 TestType 列分组，但如果 TestType 相同，则 Result 应拆分为列

CREATE TABLE Result(WorkOrder varchar(10), TestType varchar(20), Result decimal(10,2));
INSERT INTO Result (WorkOrder, TestType, Result) VALUES 
('HP19002316','VitaminA', 10.3),
('HP19002316','VitaminA', 11.3),
('HP19002316','VitaminA', 12.3),
('HP19002316','VitaminB', 13.4),
('HP19002316','VitaminB', 14.4),
('HP19002316','VitaminC', 15.5),
('HP19002316','VitaminD', 17.0)

我希望 SQL 以这种格式返回数据

WorkOrder       TestType        Result1   Result2  Result3 
==========================================================
HP19002316      VitaminA        10.3        11.3    12.3    
HP19002316      VitaminB        13.4        14.4    NULL
HP19002316      VitaminC        15.5        NULL    NULL
HP19002316      VitaminD        17.0        NULL    NULL

Result# 列应该是动态的，因为每个 TestType 都有很多结果

Answer 1

正如我在 cmets 中提到的，您需要的是 PIVOT 或交叉表；我更喜欢后者，所以我将使用它。

对此的非动态解决方案如下：

WITH RNs AS(
    SELECT WorkOrder,
           TestType,
           Result,
           ROW_NUMBER() OVER (PARTITION BY WorkOrder, TestType ORDER BY (SELECT NULL)) AS RN --ORDER BY should be your ID/always ascending column
    FROM dbo.Result)
SELECT WorkOrder,
       TestType,
       MAX(CASE RN WHEN 1 THEN Result END) AS Result1,
       MAX(CASE RN WHEN 2 THEN Result END) AS Result2,
       MAX(CASE RN WHEN 3 THEN Result END) AS Result3
FROM RNs R
GROUP BY WorkOrder,
         TestType;

但是，问题在于这会将您“锁定”为 3 个结果，但您建议结果的数量不确定。因此，您需要一个动态的解决方案。

以下最多可得到 100 个结果。如果您确实需要多于多列，则在 CTE Tally 中将更多 CROSS JOINs 添加到 N。这个结果是这样的（相当混乱）。

DECLARE @SQL nvarchar(MAX),
        @CRLF nchar(2) = NCHAR(13) + NCHAR(10),
        @MaxTally int;

SELECT @MaxTally = MAX(C)
FROM (SELECT COUNT(*) AS C
      FROM dbo.Result
      GROUP BY WorkOrder,
               TestType) R;

WITH N AS(
    SELECT N
    FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL))N(N)),
Tally AS(
    SELECT TOP (@MaxTally) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS I
    FROM N N1, N N2) --100 rows, add more Ns for more rows
SELECT @SQL = N'WITH RNs AS(' + @CRLF +
              N'    SELECT WorkOrder,' + @CRLF +
              N'           TestType,' + @CRLF +
              N'           Result,' + @CRLF +
              N'           ROW_NUMBER() OVER (PARTITION BY WorkOrder, TestType ORDER BY (SELECT NULL)) AS RN --ORDER BY should be your ID/always ascending column' + @CRLF +
              N'    FROM dbo.Result)' + @CRLF +
              N'SELECT WorkOrder,' + @CRLF +
              N'       TestType,' + @CRLF +
              --Using FOR XML PATH due to not knowing SQL Server version
              STUFF((SELECT N',' + @CRLF +
                            CONCAT(N'       MAX(CASE RN WHEN ',T.I,N' THEN Result END) AS Result',T.I)
                     FROM Tally T
                     ORDER BY T.I ASC
                     FOR XML PATH(N''),TYPE).value('(./text())[1]','nvarchar(MAX)'),1,3,N'') + @CRLF +
              N'FROM RNs R' + @CRLF +
              N'GROUP BY WorkOrder,' + @CRLF +
              N'         TestType;';

PRINT @SQL; --Your best friend.

EXEC sys.sp_executesql @SQL;

Answer 2

你可以试试这个并扩展逻辑。

select *,((select Result from (select TestType,Result, ROW_NUMBER() over ( PARTITION BY testtype ORDER BY  Testtype) Id from Result) a where a.Id='1' and a.TestType=b.TestType )) Result1,
((select Result from (select TestType,Result, ROW_NUMBER() over ( PARTITION BY testtype ORDER BY  Testtype) Id from Result) a where a.Id='2' and a.TestType=b.TestType )) Result2,
((select Result from (select TestType,Result, ROW_NUMBER() over ( PARTITION BY testtype ORDER BY  Testtype) Id from Result) a where a.Id='3' and a.TestType=b.TestType )) Result3
 from (
select Max(WorkOrder) WorkOrder,TestType from Result group by TestType ) b