Re: Looking for "gaps" (from a time perspective) in data

On 10 okt, 11:53, jeremy <jeremy0..._at_gmail.com> wrote:
> This is on 10gR2 standard edition.
>
> We have a table defined like this:
>
> txn_id
> date_start
> date_end
> url_called
>
> which contains a record for every time our application processes a
> request from a browser. We would like to be able to spot any "gaps" in
> the data - which would indicate a period when the service was
> unavailable for whatever reason.
>
> To do this we need to do a comparison between the date_start of each
> row and the one that preceded (or followed)  it and then see if the
> period of time is greater than a to-be-determined threshold.
>
> Can a single SQL statement be constructed which could achieve this? if
> so could you point me in the right direction? For those who haven't
> followed what I was asking about, if you are in the majority then
> please accept my apologies for not being more concise :)
>
> regards,
>
> --
> jeremy

Please refer to the LAG function in the Analytical Functions chapter in the Datawarehousing documentation for the version you don't care to mention.
Please apologize for being *too* concise. At a minimum you should always post your 4 digit version number. If you can't be bother to do it, please consider not posting at all. Crystal balls have been worn out by similar lazy dudes like you.

--
Sybrand Bakker
Senior Oracle DBA