Analyze log table - Oracle 11g

Question

I have this table on Oracle 11g:

CREATE TABLE USER.HISTORY_LOG
(
  ID                       NUMBER,
  DATE                     DATE,
  COUNT_INSERTED_ROWS      NUMBER,
  EXEC_TIME                VARCHAR2(50 BYTE)
)

Some data:

ID      DATE                COUNT_INSERTED_ROWS EXEC_TIME

6356    04/04/2016 09:36:03 1074    00h:00m:58s:769ms
6355    04/04/2016 09:33:00 1074    00h:00m:56s:221ms
6354    04/04/2016 09:30:11 1074    00h:01m:06s:719ms
6353    04/04/2016 09:27:13 1074    00h:01m:08s:977ms
6352    04/04/2016 09:24:13 1074    00h:01m:09s:361ms
6351    04/04/2016 09:21:12 1074    00h:01m:07s:685ms
6350    04/04/2016 09:18:11 1074    00h:01m:06s:657ms
6349    04/04/2016 09:15:01 1074    00h:00m:57s:074ms

This table is fed by a console app writen in c#, which runs every 3 minutes "forever"... But it can crash by some server's issue like unavailability.. and I must check if there was any time - and when - this happened. how can I do that using SQL? What I need is something like that:

Between date X and Y, it took more than 3 minutes to execute.

I want to solve using SQL.... is there any way I can do that? I confess that I'm out of ideas to build a query to do that.

Answer 1

You can try with something like this:

select *
from (
    select lag(date_)over ( order by date_) as date_before_ko,
           date_ as date_after_ko,
           floor((date_ - lag(date_) over ( order by date_))*24*60) as minutes_passed  
    from HISTORY_LOG
)
where minutes_passed > 4

This computes, for each row, the preceeding record and checks if the difference in minutes between the two dates is more than 4.