循环遍历表以创建临时表

Question

我有一张表，其中有一个日期字段是周数，然后是 7 个十进制字段表示工作时间。

我想遍历这个表，并在一个临时表中为一周中的每一天创建一行，其中包含每天的工作时间。

我可以做一个简单的...

SELECT  UserID, WeekNum, Hours1, Hours2, Hours3, Hours4, Hours5, Hours6, Hours7
INTO    #NCExtract
FROM    Timesheet

但我需要有结果

UserID Date Hours
UserID Date Hours
UserID Date Hours
UserID Date Hours
UserID Date Hours
UserID Date Hours
UserID Date Hours

从一排开始。于是我开始了以下方式：

create table #NCExtract
(
    UserID int, 
    WorkDate DateTime, 
    WorkHours decimal
) 

Select *
From   TimeSheetTable

While (Select Count(*) From TimeSheetTable) > 0
Begin
    Create #NCExtract record with 1st date hours
    Create #NCExtract record with 2nd date hours
    Create #NCExtract record with 3rd date hours
    Create #NCExtract record with 4th date hours
    Create #NCExtract record with 5th date hours
    Create #NCExtract record with 6th date hours
    Create #NCExtract record with 7th date hours
End

我不确定如何在循环中提供信息来创建记录。

Answer 1

我可以想出两种方法来做你想做的事（假设是 t-sql，但也应该适用于其他数据库）。

unpivot :https://technet.microsoft.com/en-us/library/ms177410(v=sql.105).aspx

或 7 个选择语句（粗略估计见下文）

--Since i do not have a table definition of timesheet table might be a little off
create table #NCExtract ( UserID int, WorkDate DateTime, WorkHours decimal )

insert into #NCExtract (UserID, WorkDate, WorkHours)
Select Userid, DateAdd(d,1,WeekNum), Hours1 -- I assumed that the weeknum column was a date/datetime
From TimeSheetTable 
Where Hours1 is not null -- add any needed logic (e.g. not null or <> 0)

insert into #NCExtract (UserID, WorkDate, WorkHours)
Select Userid, DateAdd(d,2,WeekNum), Hours2 --update the date add for each select
From TimeSheetTable
Where Hours2 is not null

--3, 4, 5, 6 ommited

select * from #NCExtract 
order by UserID, WorkDate -- if the final result needs to be sorted, sort when selecting