Question

I’ve datasets in a table with a timestamp value and an event string. How can I get all events that are min. 5 seconds apart of other events with the same event value.

Data given:

TS                         EVENT                           
-------------------------- --------------------------------
2012-03-15 13:09:27.486000 foo                             
2012-03-15 13:09:37.253000 bar                             
2012-03-15 13:09:31.243000 foo                             
2012-03-15 13:09:26.243000 foo                             
2012-03-15 13:09:47.841000 foo                             

The result should be

TS                         EVENT                           
-------------------------- --------------------------------
2012-03-15 13:09:26.243000 foo                             
2012-03-15 13:09:37.253000 bar                             
2012-03-15 13:09:47.841000 foo                             

Two of the “foo” events are only 3 or 4 seconds before or after another “foo” event and should therefore not be selected. If multiple event exists in a certain range of seconds, only the first one should be returned.

Any hint appreciated! Thanks!

Answer 1

Try:

with cte as 
(select event, ts, row_number() over (partition by event order by ts) rn
 from myTable)
select t1.event, t1.ts
from cte t1
left join cte t2 
       on t2.event = t1.event and 
          t2.rn=t1.rn+1 and 
          t2.ts <= t1.ts + interval '5' second
where t2.event is null