如何在求和另一列时返回列的最后一个值？

Question

我有一个查询汇总消费数据直到某个日期时间@end。但是，当行按trans_num（交易号）排序时，我还需要返回另一列Employee的最后一个值。我该怎么做呢？

我到目前为止所尝试的是：我试过使用SELECT Top 1，但这不会给我每个项目的最后一名员工。该表具有trans_num作为主键，并且所有其他字段不是唯一的。我可以根据需要提供任何其他信息。

declare @start datetime2 = '7/17/17 05:00:00 AM' 
declare @end datetime2 = '7/18/17 05:00:00 AM' 
declare @job varchar(12) = 'W000017154' 
declare @suf int = 29 

select 

    t.item 
    , i.description 
    , sum(t.qty) as sumqty 
    , t.ref_num 
    , t.ref_line_suf 
    , (select top 1 

      t.emp_num 

     from 

      isw_lptrans as t 

     where 

      t.ref_num = @job 
      and t.ref_line_suf = @suf 
      and t.createdate between @start and @end 

     order by 

      trans_num desc 

    ) as lastemp 

from 

    isw_lptrans as t 
    inner join item as i on i.item = t.item 

where 

    t.trans_type = 'I' 
    and t.createdate between @start and @end 
    and t.ref_num = @job 
    and t.ref_line_suf = @suf 

group by 

    t.item 
    , i.description 
    , t.ref_num 
    , t.ref_line_suf 

行的截图：突出显示的行中指定的日期时间@end当最后一排。所以我需要总结qty列，但也返回emp_num（员工列）中的最后一个值。因此在下面的屏幕截图中，总数应为1000，而将TG43499作为emp_num列的最后一个值返回。

Answer 1

您可以使用公用表表达式（CTE）和RANK函数，作为一个子查询将返回最后一个员工办理的每个项目？

此查询可能不完全正常工作，但它可以让你开始：

declare @start datetime2 = '7/17/17 05:00:00 AM' 
declare @end datetime2 = '7/18/17 05:00:00 AM' 
declare @job varchar(12) = 'W000017154' 
declare @suf int = 29 

with lastEmp as (
    select 
    t.emp_num 
    , t.item 
    , RANK() OVER (PARTITION BY t.item ORDER BY t.CreateDate DESC) AS rankValue 
    FROM isw_lptrans as t 
    WHERE t.ref_num = @job 
    and t.ref_line_suf = @suf 
    and t.createdate between @start and @end 
) 
select 
    t.item 
    , i.description 
    , sum(t.qty) as sumqty 
    , t.ref_num 
    , t.ref_line_suf 
    , le.emp_num lastEmployeeNum 
from 
    isw_lptrans as t 
inner join item as i on i.item = t.item 
inner join lastEmp le ON t.item = le.item AND le.rankValue = 1 
where 
    t.trans_type = 'I' 
    and t.createdate between @start and @end 
    and t.ref_num = @job 
    and t.ref_line_suf = @suf 
group by 
    t.item 
    , i.description 
    , t.ref_num 
    , t.ref_line_suf