Question

我有一张表TBL_Student：

RollNo  Name    Subject Month   Year    Marks   Start_Date  End_Date
---------------------------------------------------------------------
1        A       MATH   JAN     2016     65      01-Jan-16  31-Jan-16
1        A       MATH   FEB     2016     65      01-Feb-16  29-Feb-16
1        A       MATH   MAR     2016     70      01-Mar-16  31-Mar-16
1        A       MATH   APR     2016     65      01-Apr-16  30-Apr-16
1        A       MATH   MAY     2016     65      01-May-16  31-May-16
1        A       MATH   JUN     2016     65      01-Jun-16  30-Jun-16
1        A       MATH   JUL     2016     82      01-Jul-16  31-Jul-16
1        A       MATH   AUG     2016     70      01-Aug-16  31-Aug-16
1        A       MATH   SEP     2016     70      01-Sep-16  30-Sep-16
1        A       MATH   OCT     2016     56      01-Oct-16  31-Oct-16
1        A       MATH   NOV     2016     65      01-Nov-16  30-Nov-16
1        A       MATH   DEC     2016     65      01-Dec-16  31-Dec-16
1        A       MATH   JAN     2017     86      01-Jan-17  31-Jan-17

我需要这样的输出

RollNo  Name    Subject Marks   Start_Date  End_Date
-----------------------------------------------------
 1       A       MATH    65      01-Jan-16  29-Feb-16
 1       A       MATH    70      01-Mar-16  31-Mar-16
 1       A       MATH    65      01-Apr-16  30-Jun-16
 1       A       MATH    82      01-Jul-16  31-Jul-16
 1       A       MATH    70      01-Aug-16  30-Sep-16
 1       A       MATH    56      01-Oct-16  31-Oct-16
 1       A       MATH    65      01-Nov-16  31-Dec-16
 1       A       MATH    86      01-Jan-17  31-Jan-17

如果连续标记相同，则它将出现一次，但是第一个标记的开始日期和最后一个标记结束。

到目前为止我尝试过的，但是没有工作：

SELECT 
    RollNO, Name, Subject, Marks,
    Start_Date, End_Date
FROM 
    (SELECT 
         ROW_NUMBER() OVER (ORDER BY Start_Date ASC) RNUM,
         RollNO, Name, Subject, Marks,
         Start_Date, End_Date
     FROM 
         TBL_Student
     WHERE 
         RollNo = 1
         AND Subject = 'MATH') A

Answer 1

试试这个：

select
    rollNo, Name, subject, marks,
    min(start_date) start_date, max(end_date) end_date
from (
    select
        t.*, sum(x) over (partition by rollNo, subject order by start_date) grp
    from (
        select
            t.*, case when marks = lag(marks,1,marks) over 
                   (partition by rollNo, subject order by start_date) 
                 then 0 else 1 end x
        from your_table t
    ) t
) t
group by rollNo, Name, subject, marks, grp;

它根据标记和start_date创建组，然后找到所需的聚合。

需要帮助SQL查询返回不同的值

1 个答案: