Re: join on next row

Thank you for responding.
I was thinking along those lines as well, though that would be an
absolute performance killer.

Gurjeet Singh wrote:
> It would have been quite easy if done in Oracle's 'lateral view'
> feature. But I think it is achievable in standard SQL too; using
> subqueries in the select-clause.
>
> Try something like this:
>
> select
> Employee, EventDate,
> EventTime as e1_time,
> EventType as e1_type,
> ( select
> EventTime
> from
> Events
> where Employee = O.Employee
> and EventDate = O.EventDate
> and EventTime > O.EventTime
> limit 1
> )as e_time_1,
> ( select
> EventType
> from
> Events
> where Employee = O.Employee
> and EventDate = O.EventDate
> and EventTime > O.EventTime
> limit 1
> )
> from
> Events
>
> Hope it helps...
>
> Regards,
> Gurjeet.
>
> On 6/20/06, Sim Zacks <sim(at)compulab(dot)co(dot)il> wrote:
>> I am having brain freeze right now and was hoping someone could help me
>> with a (fairly) simple query.
>>
>> I need to join on the next row in a similar table with specific criteria.
>>
>> I have a table with events per employee.
>> I need to have a query that gives per employee each event and the event
>> after it if it happened on the same day.
>>
>> The Events table structure is:
>>
>> EventID
>> Employee
>> EventDate
>> EventTime
>> EventType
>>
>> I want my query resultset to be
>> Employee,EventDate(1),EventTime(1),EventType(1),EventTime(2),EventType(2)
>> Where Event(2) is the first event of the employee that took place after
>> the other event.
>>
>> Example
>> EventID Employee EventDate EventTime EventType
>> 1 John 6/15/2006 7:00 A
>> 2 Frank 6/15/2006 7:15 B
>> 3 Frank 6/15/2006 7:17 C
>> 4 John 6/15/2006 7:20 C
>> 5 Frank 6/15/2006 7:25 D
>> 6 John 6/16/2006 7:00 A
>> 7 John 6/16/2006 8:30 R
>>
>> Expected Results
>> John, 6/15/2006, 7:00, A, 7:20, C
>> Frank, 6/15/2006, 7:15, B, 7:17, C
>> Frank, 6/15/2006, 7:17, C, 7:25, D
>> John, 6/16/2006, 7:00, A, 8:30, R
>>
>> To get this result set it would have to be an inner join on employee and
>> date where the second event time is greater then the first. But I don't
>> want the all of the records with a greater time, just the first event
>> after.
>>
>> Thank You
>> Sim
>>
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