Question

我们的ERP系统中的一个数据库表只包含这样定价的有效日期：

Partnumber ||Effective Date  || Price
----------------------------------------------
abc             || 2012-01-01    ||  $ 1,00
abc             || 2012-02-01    ||  $ 1,10   
xyz             || 2012-01-01    ||  $ 1,00

我的尺寸表如下：

Partnumber  |Start Date       ||  EndDate        || Price
-----------------------------------------------------------------
abc             || 2012-01-01    ||  2012-01-31   ||$ 1,00
abc             || 2012-02-01    ||  <NULL>        ||$ 1,00
xyz             || 2012-01-01    ||  <NULL>        ||$ 1,00

这使我能够根据StartDate和EndDate之间的orderdate（或EndDate IS NULL）找到合适的价格

最后我的问题：如果有一个新的EffectiveDate的新记录，我怎么能更新EndDate enddate = new recored startDate-1。

Answer 1

表中的startdate定义为varchar（20）＆amp;结束日期为int。这是一个错误吗？我不确定你希望将结束日期（作为int）设置为，因为它比新的startdate少1。

我的代码可以完成这项工作，包括datetime或smalldatetime数据类型的startdates和enddates。如果你的表实际上是你给出的结构，你将不得不相应地调整逻辑。

这个逻辑应该放在存储过程中。

declare stageCursor cursor scroll for 
    select name, startdate, enddate from staging;

declare @name varchar(20), 
        @startdate datetime, 
        @enddate datetime;

open stageCursor
fetch next from stageCursor into @name, @startdate, @enddate
while @@fetch_status = 0 begin
    update operations set o.enddate = dateadd(d, -1, s.startdate) 
    where name = @name --does this need to be restricted to just the latest operations row somehow?

    insert operations (name, startdate, enddate)
    values (@name, @startdate, @enddate);

    fetch next from stageCursor into @name, @startdate, @enddate
end

close stageCursor
deallocate stageCursor

truncate table staging   --I presume after the data has been used to update the
                         --operations table, it isnt going to wanted anymore

Answer 2

试试这个：

with t as
(
select 
    row_number() over (partition by Partnumber order by [Effective Date]) as row_id,
    *
from your_table
)
select
    t_start.Partnumber,
    t_start.[Effective Date] as start_dt,
    dateadd(day,-1,t_end.[Effective Date]) as end_dt,
    t_start.Price
from 
    t as t_start
left join 
    t as t_end
on 
    t_start.row_id+1 = t_end.row_id and t_start.Partnumber=t_end.Partnumber

<强>更新

如果你想更新your_table中的end_date，你可以：

update your_table
set end_dt = (select dateadd(day,-1,min(t.start_dt)) from your_table t 
              where t.Partnumber=your_table.Partnumber 
              and t.start_dt>your_table.start_dt);

结果可能会有两个连续期间的重复价格，此处为the approach以解决此问题。

您可以使用此SQL FIDDLE DEMO进行测试。

如何使用enddate = new recored startDate - 1插入新记录并更新旧记录？

2 个答案: