Question

我有一个像下面这样的表，在今天的EntryTime列中有条目。

表1

PersonID|StartTime|EndTime|EntryTime
1       |10:00    |12:00  |2014-01-01
1       |10:00    |12:00  |2014-01-02
1       |10:00    |12:00  |2015-01-03
...

和合同表：

表2

PersonID|ContractID| ContractStart| ContractType|Hours
1       |1         |2014-01-01    |Student      |8
1       |2         |2015-01-01    |Trainee      |40
1       |3         |2015-03-01    |Student      |20
1       |4         |2015-05-01    |Student      |12

现在，我想使用下面提到的结果表将当前(datediff(minute, StartTime, Endtime))的时间contractType相加。从最后一个开始，contracttype必须是连续的。因此，在此示例中，合同3 + 4的所有条目都是相关的。

我的想法是使用loop来选择相关合同。

WHILE (Select ContractType from Table2) = 'Student'
Begin
Select ContractStart from Table2
Order By ContractStart
End

不幸的是循环还没有工作，如果我不知道如何将它实现到where子句中。

我想要获得的结果表是subset Table1，所有条目均从2015-03-01开始

Answer 1

如果没有示例，很难知道你想要什么，但这是一次尝试。还要对你的类型做出很多猜测。

注意：Avoid while循环和游标，坚持使用set logic =）

declare @Table1 as table
(
    PersonID int
    ,StartTime datetime
    ,EndTime datetime
    ,EntryTime date
)

insert into @Table1
values
 (1       ,'10:00', '12:00', '2014-01-01')
,(1       ,'10:00', '12:00', '2014-01-02')
,(1       ,'10:00', '12:00', '2015-01-03')
,(2       ,'10:00', '12:00', '2015-01-03')
,(2       ,'10:00', '12:00', '2015-01-04')
,(3       ,'10:00', '12:00', '2015-01-03')
,(3       ,'10:00', '12:00', '2015-01-05')


declare @Table2 as table
(
    PersonID int
    ,ContractID int
    ,ContractStart date
    ,ContractType varchar(10)
    ,[Hours] float
)
insert into @Table2
values
 (1       ,1         ,'2014-01-01',    'Student',      8)
,(1       ,2         ,'2015-01-01',    'Trainee',      40)
,(1       ,3         ,'2015-03-01',    'Student',      20)
,(1       ,4         ,'2015-05-01',    'Student',      12)
,(2       ,1         ,'2014-01-01',    'Student',      8)
,(2       ,2         ,'2015-01-01',    'Trainee',      40)
,(2       ,3         ,'2015-03-01',    'Student',      20)
,(2       ,4         ,'2015-05-01',    'Student',      12)
,(3       ,1         ,'2014-01-01',    'Student',      8)
,(3       ,2         ,'2015-01-01',    'Trainee',      40)
,(3       ,3         ,'2015-03-01',    'Student',      20)
,(3       ,4         ,'2015-05-01',    'Student',      12)

--Current contrat (for PersonId = 1)
declare @CurrentType varchar(10) =
(select top 1 ContractType from @Table2 where PersonID = 1 order by ContractStart desc)

--Last different type start (for PersonId = 1)
declare @LastDiff date = 
(select top 1 ContractStart from @Table2 where PersonID = 1 and @CurrentType != ContractType order by ContractStart desc)

--Current type span (for PersonId = 1)
select datediff(minute, min(StartTime + cast(EntryTime as datetime)), max(EndTime + cast(EntryTime as datetime))) as [PesonId = 1 TimeSpan]
from @Table1
where PersonID = 1
and EntryTime > @LastDiff


-- Puting everything togheter
select t1.PersonId, datediff(minute, min(t1.StartTime + cast(t1.EntryTime as datetime)), max(t1.EndTime + cast(t1.EntryTime as datetime))) as TimeSpan
from @Table1 t1
where t1.EntryTime >
 (
    select top 1 t2.ContractStart
    from @Table2 t2
    where t2.PersonID = t1.PersonID
    and t2.ContractType != 
    (
       select top 1 t2b.ContractType from @Table2 t2b where t2b.PersonID = t2.PersonID order by t2b.ContractStart desc
    )
    order by t2.ContractStart desc
 )
group by t1.PersonId

该片段是不言自明的，并告诉我：

PersonId TimeSpan
-------- --------
       1    120
       2    1560
       3    3000

注意我添加了一些数据以便制作更好的测试示例

Answer 2

试试这个：

Select Table1.PersonID, ContractID, datediff(minute, StartTime, Endtime) diff
    from Table2 INNER JOIN Table1 on Table2.PersonID = Table1.PersonID
    WHERE ContractType LIKE 'Student'
    GROUP BY Table1.PersonID, ContractID

如何在where子句中使用While循环

2 个答案: