访问SQL - 如何在从最新日期选择时防止交替日期

Question

我有两张桌子并输出

用于获取输出的SQL是

SELECT t.empID, t.timesheet, r.Rate AS RateBilled
FROM Rates AS r, timesheet AS t
WHERE (((r.empid)=t.empid) And ((t.timeSheet)>=r.promotionDate))
GROUP BY t.empID, t.timesheet, r.Rate , r.promotiondate
HAVING (((r.promotionDate)=Max([r].[promotionDate])));

我的问题是输出表的第5行和第7行也应该在Ratebilled中使用$ 15（因为emp 01的促销日期可能是/ 1），但它似乎仍然使用最初的Jan-1速率。任何帮助表示赞赏。

Answer 1

 select m.*, r2.rate from  
 (SELECT t.empID, t.timesheet,
 max(r.promotiondate) as promotiondate FROM timesheet AS t left join
 rates r on r.empid=t.empid And t.timeSheet>=r.promotionDate  
 group by t.empid, t.timesheet) m 
 inner join rates r2 on  m.empid=r2.empid and m.promotiondate=r2.promotionDate

Answer 2

你可以试试这个

select  t.empID, t.timesheet
        , (select top 1 rate from Rates where Rates.empID = t.empID and Rates.PromotionDate <= t.timesheet order by Rates.PromotionDate desc) as RateBilled
from    timesheet as t

希望能帮助你。