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SQL query

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Topic

sudipbh
Starting Member

3 Posts

Posted - 2008-04-17 : 07:09:17

Hello all,

Here is one scenario that: I need one query based on one table which is having data like:

RequestId Dept Date
1001 1 10/10/2008 9:30
1001 2 10/10/2008 9:31
1001 1 10/10/2008 11:40
1001 3 10/10/2008 11:55

I have to find out the difference between 2 consecutive dates like:
diffenrece between (10/10/2008 9:30 and 10/10/2008 9:31) then (10/10/2008 9:31 and 10/10/2008 11:40) and so on.

I have to do it using SQL query only in SQl server 2005.
There is no primary key field in the table and i can't create one extra columns also.

Can anyone help me with this? urgent.

Thanks & Regards,
Sudip

RyanRandall
Master Smack Fu Yak Hacker

1074 Posts

Posted - 2008-04-17 : 07:22:27

Here's one way...

 
--Preparation (you may not need some of this if you have it already)
declare @t table (RequestId int, Dept int, Date datetime)
insert @t
          select 1001, 1, '10/10/2008 9:30'
union all select 1001, 2, '10/10/2008 9:31'
union all select 1001, 1, '10/10/2008 11:40'
union all select 1001, 3, '10/10/2008 11:55'

--Query (the bit you need)
select *, datediff(minute, (select top 1 Date from @t where Date < a.Date order by Date desc), Date) as MinutesSincePreviousEntry from @t a

 /* Results
RequestId   Dept        Date                    MinutesSincePreviousEntry
----------- ----------- ----------------------- -------------------------
1001        1           2008-10-10 09:30:00.000 NULL
1001        2           2008-10-10 09:31:00.000 1
1001        1           2008-10-10 11:40:00.000 129
1001        3           2008-10-10 11:55:00.000 15
*/

Ryan Randall
Solutions are easy. Understanding the problem, now, that's the hard part.

sudipbh
Starting Member

3 Posts

Posted - 2008-04-17 : 07:56:48

Thanks very much for the solution.

johnsql
Posting Yak Master

161 Posts

Posted - 2008-05-29 : 10:06:11

quote:

Originally posted by RyanRandall

Here's one way...

 
--Preparation (you may not need some of this if you have it already)
declare @t table (RequestId int, Dept int, Date datetime)
insert @t
          select 1001, 1, '10/10/2008 9:30'
union all select 1001, 2, '10/10/2008 9:31'
union all select 1001, 1, '10/10/2008 11:40'
union all select 1001, 3, '10/10/2008 11:55'

--Query (the bit you need)
select *, datediff(minute, (select top 1 Date from @t where Date < a.Date order by Date desc), Date) as MinutesSincePreviousEntry from @t a

 /* Results
RequestId   Dept        Date                    MinutesSincePreviousEntry
----------- ----------- ----------------------- -------------------------
1001        1           2008-10-10 09:30:00.000 NULL
1001        2           2008-10-10 09:31:00.000 1
1001        1           2008-10-10 11:40:00.000 129
1001        3           2008-10-10 11:55:00.000 15
*/

Ryan Randall
Solutions are easy. Understanding the problem, now, that's the hard part.

Is there some way to solve the problem using JOIN clause?
Thanks.

RyanRandall
Master Smack Fu Yak Hacker

1074 Posts

Posted - 2008-05-29 : 10:16:25

Here's one way...

select a.RequestId, a.Dept, a.Date, datediff(minute, max(b.Date), a.Date) as MinutesSincePreviousEntry
from @t a left outer join @t b on a.Date > b.Date group by a.RequestId, a.Dept, a.Date order by a.Date

Ryan Randall
Solutions are easy. Understanding the problem, now, that's the hard part.

TG
Master Smack Fu Yak Hacker

6065 Posts

Posted - 2008-05-29 : 10:18:53

And another way:


--Preparation (you may not need some of this if you have it already)
declare @t table (RequestId int, Dept int, Date datetime)
insert @t
          select 1001, 1, '10/10/2008 9:30'
union all select 1001, 2, '10/10/2008 9:31'
union all select 1001, 1, '10/10/2008 11:40'
union all select 1001, 3, '10/10/2008 11:55'

 ;with cte (requestid, dept, date, rn)
as (
select RequestId, Dept, Date, row_number() over (order by Date)
from   @t
)
select a.requestid, a.dept, a.date, datediff(minute, b.date, a.date) MinutesSincePreviousEntry
from   cte a
left join cte b on b.rn+1=a.rn

/* Results
requestid   dept        date                    MinutesSincePreviousEntry
----------- ----------- ----------------------- -------------------------
1001        1           2008-10-10 09:30:00.000 NULL
1001        2           2008-10-10 09:31:00.000 1
1001        1           2008-10-10 11:40:00.000 129
1001        3           2008-10-10 11:55:00.000 15
*/

Be One with the Optimizer
TG

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2008-05-29 : 12:59:03

Another Method:-

SELECT t.RequestId,t.Dept,t.Date,
DATEDIFF(mi,t.Date,t1.NextDate) AS MinutesSincePreviousEntry
FROM Table t
OUTER APPLY (SELECT MIN(Date) AS NextDate
             FROM Table
             WHERE Date > t.Date) t1

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