Question

我尝试使用CASE / WHEN来解决下面的问题，但我一直在寻找确切的解决方案。以下是预期结果后面的问题。需要你的帮助。

考虑下表EmpComp

NAME        COMPANY        START_DATE        END_DATE        IS_ACTIVE
-----------------------------------------------------------------------
Kiran       TCS            01-Apr-2015       31-May-2015     0
Kiran       TCS            15-Apr-2015       31-May-2015     1
Kiran       TCS            15-Jun-2015       30-Jun-2015     1
Mike        ABC            01-Jan-2015       31-Jan-2015     0
Mike        ABC            01-Feb-2015       31-Mar-2015     0
Pawan       XYZ            01-Dec-2015       31-Dec-2015     1

结果应为：结果表再次解释逻辑。

NAME        COMPANY        START_DATE        END_DATE        IS_ACTIVE
-----------------------------------------------------------------------
Kiran       TCS            15-Apr-2015       30-Jun-2015     1 (only the records with 1 are considered and start_date, end_date should cover the complete end to end range for is_active = 1, incld any gap days.
Mike        ABC            01-Feb-2015       31-Mar-2015     0 (when all the grouped records have is_active = 0, only the last one is shown)
Pawan       XYZ            01-Dec-2015       31-Dec-2015     1

或

NAME        COMPANY        START_DATE        END_DATE        IS_ACTIVE
-----------------------------------------------------------------------
Kiran       TCS            15-Apr-2015       30-Jun-2015     1 (same logic as above for some of grouped records with is_active = 1)
Mike        ABC            01-Jan-2015       31-Jan-2015     0 (it is ok to show all the grouped records that have all 0s for is_active)
Mike        ABC            01-Feb-2015       31-Mar-2015     0
Pawan       XYZ            01-Dec-2015       31-Dec-2015     1

逻辑：

记录按名称/公司
对于IS_ACTIVE标志设置为1的某些记录时的每个分组，然后忽略具有IS_ACTIVE = 0的组的记录，
显示START_DATE，END_DATE以涵盖IS_ACTIVE = 1的完整日期范围。
如果分组全部为0，则可以按原样显示所有记录，或者更好地仅显示0的最后一条记录。否则，如果只有一个/所有记录为0，则保持原样

Answer 1

将聚合函数与CASE表达式一起使用：

SELECT
    Name,
    Company,
    Start_Date =
        CASE
            WHEN SUM(CASE WHEN Is_Active = 1 THEN 1 ELSE 0 END) > 0 
                THEN MIN(CASE WHEN Is_Active = 1 THEN Start_Date END)
            ELSE
                MAX(Start_Date)
        END,
    End_Date =
        CASE
            WHEN SUM(CASE WHEN Is_Active = 1 THEN 1 ELSE 0 END) > 0 
                THEN MAX(CASE WHEN Is_Active = 1 THEN End_Date END)
            ELSE
                MAX(End_Date)
        END,
    Is_Active = 
        CASE
            WHEN SUM(CASE WHEN Is_Active = 1 THEN 1 ELSE 0 END) > 0  THEN 1
            ELSE 0
        END
FROM #EmpComp 
GROUP BY
    Name, Company
ORDER BY
    Name, Company

DEMO

Answer 2

您可以使用view和Union Query

来完成

1：创建包含1

记录的视图

**

Create View My_View as 
Select NAME,COMPANY,MIN(STAR_DATE) as START_DATE ,MAX(END_DATE) as END_DATE
From MY_TABLE
Where IS_ACTIVE=1 group by NAME,COMPANY

**

MY_VEW包含有1的记录，实际上每次都是一个表你的桌子改变了原子改变的

2：使用UNION生成2个SQLS

     2.1 :The first display records from our view  .

    2.2: Second display records with 0 that their key not exist in our view

**

Select * from My_View (First Query 
(In case that you do not want all records in view you can use where exactly like table)
Union 
Select A. NAME,A.COMPANY,A.START_DATE,A.END_DATE   
from My_Table as A left join MY_View as B on A.Name=B.NAME
And  A.COMPANY=B.COMPANY where B.NAME IS NULL and B.COMPANY IS_NULL

**

MS SQL：条件CASE，WHEN用于GROUPED记录

2 个答案: