将 GROUP BY 结果拆分到不同的列中

Question

我有一列包含日期范围和与特定 ID（一对多）关联的天数，基于与之关联的记录数，我希望将这些结果分成几列而不是单独的行，所以从这个：

id_hr  dd beg          end
----------------------------------------
1      10 05/01/2019   15/01/2019
1      5  03/02/2019   08/02/2019
2      8  07/03/2019   15/03/2019

可能会变成这样：

id_hr  dd beg          end        dd beg          end
--------------------------------- ---------------------
1      10 05/01/2019   15/01/2019 5  03/02/2019   08/02/2019
2      8  07/03/2019   15/03/2019

我在工作表中做了同样的事情（pivot table）但是 table 变得尽可能慢，所以我在 [=28= 中寻找更友好的方法], 我做了一个 CTE，它对关联的行进行编号，然后 select 每行并在新列中显示它们。

;WITH CTE AS(
   SELECT PER_PRO, ID_HR, NOM_INC, rut_dv, dias_dur, INI, FIN,
       ROW_NUMBER()OVER(PARTITION BY ID_HR ORDER BY SUBIDO) AS RN
   FROM dbo.inf_vac WHERE PER_PRO = 201902
)
SELECT ID_HR, NOM_INC, rut_dv,
    (case when rn = 1 then DIAS_DUR end) as DIAS_DUR1,
    (case when rn = 1 then INI end) as INI1,
    (case when rn = 1 then FIN end) as FIN1,

    (case when rn = 2 then DIAS_DUR end) as DIAS_DUR2,
    (case when rn = 2 then INI end) as INI2,
    (case when rn = 2 then FIN end) as FIN2,

    (case when rn = 3 then DIAS_DUR end) as DIAS_DUR3,
    (case when rn = 3 then INI end) as INI3,
    (case when rn = 3 then FIN end) as FIN3
FROM CTE

这让我了解了每一列应该放在但不分组的位置。使用 GROUP BY 在 CTE select.

上显示错误

rn id_hr  dd    beg          end        dd    beg          end
----------------------------------- ------------------------
1  1      10   05/01/2019   15/01/2019 NULL  NULL         NULL
2  1      NULL NULL         NULL       5     03/02/2019   08/02/2019
1  2      8    07/03/2019   15/03/2019 NULL  NULL         NULL

有没有办法在第二个 select 上对它们进行分组？

Answer 1

是的，您可以 GROUP BY 所有非 CASE 列，并将 MAX 应用于每个 CASE 表达式列。

Answer 2

结果集中有查询中没有的其他列。但是，这应该有效：

SELECT ID_HR,
       max(case when rn = 1 then DIAS_DUR end) as DIAS_DUR1,
       max(case when rn = 1 then INI end) as INI1,
       max(case when rn = 1 then FIN end) as FIN1,

       max(case when rn = 2 then DIAS_DUR end) as DIAS_DUR2,
       max(case when rn = 2 then INI end) as INI2,
       max(case when rn = 2 then FIN end) as FIN2,

       max(case when rn = 3 then DIAS_DUR end) as DIAS_DUR3,
       max(case when rn = 3 then INI end) as INI3,
       max(case when rn = 3 then FIN end) as FIN3
FROM CTE
GROUP BY ID_HR;

将 GROUP BY 结果拆分到不同的列中

Spliting GROUP BY results into different columns

sql

common-table-expression

sql-server-2008