T-SQL Max date and min date with value single row

Question

First of all I would like to thank the friends who helped this complex and difficult query.

I have three tables

Table 1

 StaffId     FirstName       LastName   staffType
---------------------------------------
   1          Adam            Sorme      Student 
   2          Lara            Sandra     Teacher
   3          Jack            Jones      Student

Table 2

 GateId   GateName  
 ---------------------------------------
   1        frontDoor
   2        superDoor

Table 3

Id transitionDate     GateId  StaffId 
 ---------------------------------------
1  2018-01-1 08:00:00    1     1
2  2018-01-1 10:00:00    2     1
3  2018-01-1 20:00:00    2     1
4  2018-01-2 07:00:00    1     2
5  2018-01-2 10:00:00    1     3
6  2018-01-9 12:00:00    2     2

I want the first and last movements of students for each day . Value must be set to null if no movement is available between the specified dates

transitionDate> '2018-01-1 00:00:00 000' 
 and transitionDate< '2018-01-03 00:00:00 000'

OUTPUT:

  Id     Date    MinTransitionDate    MaxTransitionDate    FirstGateName LastGateName    StaffId    StaffType
  1   2018-01-01  2018-01-1 08:00:00 2018-01-1 20:00:00    frontDoor      superDoor         1         Student
  2   2018-01-01  null                null                  null           null             3         student
  3   2018-01-02  null                null                  null           null             1         student
  4   2018-01-02  2018-01-2 10:00:00  null                 frontDoor       null             3         student

Answer 1

you can try a query like below

see working demo

create table staff(StaffId int,   FirstName  nvarchar(10),  LastName nvarchar(10),  staffType nvarchar(10))
insert into staff values
(1,'Adam','Sorme','Student') 
,(2,'Lara','Sandra','Teacher')
,(3,'Jack','Jones','Student')

go

create table gate(GateId int,  GateName  nvarchar(10))
insert into gate values
(1,'frontDoor')
,(2,'superDoor')

go
create table logs 
(Id int, transitionDate  datetime,   GateId  int, StaffId  int)
insert into logs values
(1,'2018-01-1 08:00:00',1,1)
,(2,'2018-01-1 10:00:00',2,1)
,(3,'2018-01-1 20:00:00',2,1)
,(4,'2018-01-2 07:00:00',1,2)
,(5,'2018-01-2 10:00:00',1,3)
,(6,'2018-01-9 12:00:00',2,2)
go
declare @startdate datetime, @enddate datetime
select @startdate='2018-01-1 00:00:00' , @enddate='2018-01-03 00:00:00'


; with tempSet as 
(
    select 
    transitionDatetime=l.transitionDate,
    gateName=g.gateName,
    staffid=l.staffid,
    idx=
         row_number() over(partition by l.staffid order by l.transitionDate ) -
        row_number() over(partition by l.staffid,cast(l.transitionDate as date) order by l.transitionDate ),
    transitionDate=cast(l.transitionDate as date)
    from
    logs l inner join staff s on
    l.staffid=s.staffid and staffType='Student'
    join gate g on g.gateid=l.gateid
)
, groupedSet as
(
    select 
    t1.*,
    FirstGateName=t2.gatename,
    lastGateName=t3.gatename
    from
    (
        select
        staffid,
        mintransitionDate=min(transitionDatetime),
        maxtransitionDate= case when count(1)>1 then max(transitionDatetime) else null end,
        transitionDate=max(transitionDate),
        idx
        from
        tempSet 
        group by staffid,idx
    ) t1
    left join
    tempSet t2
    on t1.idx=t2.idx 
    and t1.staffid=t2.staffid and t1.mintransitionDate=t2.transitionDatetime
     left join
    tempSet t3
    on t1.idx=t3.idx 
    and t1.staffid=t3.staffid and t1.maxtransitionDate=t3.transitionDatetime
    where t1.transitionDate between @startdate and @enddate
 )

 select
 t.*,
 g.mintransitionDate,
 g.maxtransitionDate,
 g.FirstGateName,
 g.LastGateName
 from 
 groupedSet g
 right join
 (
     select 
         d,
         staffid
     from
     (
         select 
         top  (select datediff(d,@startdate, @endDate))
         d=dateadd(d,row_number() over(order by (select null))-1, @startDate)
         from
         sys.objects o1 cross join sys.objects o2
     )tally
          cross join
     staff 
     where staff.stafftype='Student'
    )t
 on cast(t.d as date)=cast(g.transitionDate as date) and t.staffid=g.staffid
 order by t.d asc, t.staffid asc

Answer 2

All insert statements:

create table #Staff (StaffId int, FirstName varchar(20), LastName varchar(20), staffType varchar(20))
insert into #Staff values
(1, 'Adam', 'Sorme', 'Student'), 
(2, 'Lara', 'Sandra', 'Teacher'),
(3, 'Jack', 'Jones', 'Student')

create table #Gates (GateId int, GateName varchar(20)) 
insert into #Gates values
(1, 'frontDoor'),
(2, 'backDoor')

create table #Transitions (Id int, transitionDate datetime, GateId int, StaffId  int)
insert into #Transitions values
(1, '2018-01-1 08:00:00', 1, 1),
(2, '2018-01-1 10:00:00', 2, 1),
(3, '2018-01-1 20:00:00', 2, 1),
(4, '2018-01-2 07:00:00', 1, 2),
(5, '2018-01-2 10:00:00', 1, 3),
(6, '2018-01-9 12:00:00', 2, 2)

In order to get desired result, you'll need CTE with all days between range. Limits (dates) of range you specify in variables included in below query.

declare @maxTransitionDate datetime, @minTransitionDate datetime
select @maxTransitionDate='2018-01-10', @minTransitionDate='2018-01-01'
;with cte as (
    select @minTransitionDate [Days]
    union all
    select dateadd(day,1,[Days]) from cte where [Days] < @maxTransitionDate
)
,cte2 as (
    select [Days], [StaffId], [FirstName], [LastName] from cte cross apply #staff where stafftype ='Student'
)

select C.[Days] [Date], C.[staffid], C.FirstName, C.LastName, A.mintransitiondate, A.[maxtransitiondate], A.firstgatename, A.lastgatename, A.staffType from (
    select T.[Date],
           T.staffid,
           T.mintransitiondate,
           case when T.maxtransitiondate <> T.mintransitiondate then T.maxtransitiondate end [maxtransitiondate],
           (select gatename from #gates where gateid = T.firstgateid) firstgatename,
           (select gatename from #gates where gateid = T.lastgateid) lastgatename,
           S.FirstName,
           S.LastName,
           S.staffType
    from (
        select [date], staffid,
               max(case when rn = 1 then transitiondate end) mintransitiondate,
               max(case when rn = cnt then transitiondate end) maxtransitiondate,
               max(case when rn = 1 then GateId end) FirstGateId,
               max(case when rn = cnt then GateId end) LastGateId
        from (
            select *, cast(transitiondate as date) [Date],
                   row_number() over (partition by staffid, cast(transitiondate as date) order by transitiondate) [rn],
                   count(*) over (partition by staffid, cast(transitiondate as date)) [cnt]
            from #Transitions
        ) a group by staffid, [date]
    ) [T] join #Staff [S] on T.staffid = S.staffid
    where S.staffType = 'Student'
) [A] right join cte2 [C] on A.[Date] = C.[Days] and A.[staffid] = C.[staffid]

Answer 3

The other answers seem so complicated.

First, use cross join to get all the rows. Then use left join and aggregation to get the information you want.

The basic query looks like this:

select s.staffId, d.dte,
       min(t.transitionDate) as first_change,
       max(t.transitionDate) as first_change,
       max(case when seqnum_asc = 1 then gateId end) as first_gateid,
       max(case when seqnum_desc = 1 then gateId end) as last_gateid
from (select s.* from Staff s where stafftype = 'Student') s cross join
     (select distinct cast(transitionDate as date) as dte from Transitions) d left join
     (select t.*,
             row_number() over (partition by StaffId, cast(transitionDate as date) order by transitionDate) as seqnum_asc,
             row_number() over (partition by StaffId, cast(transitionDate as date) order by transitionDate desc) as seqnum_desc
      from Transitions t
     ) t
     on cast(t.transitiondate as date) = d.dte and
        t.staffId = s.staffId and
        1 in (t.seqnum_asc, t.seqnum_desc)
group by s.staffId, d.dte;

You can enhance the select to bring back more columns.

Here is a SQL Fiddle.