With pre V3, PSQL (stored procedure or EXECUTE BLOCK) comes to my mind.

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Thomas Steinmaurer
http://www.upscene.com

Professional Tools and Services for Firebird
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'Piotr Olszewski' piotr.olszewski@... [firebird-support] schrieb am 29.03.2016 11:53:

> let's assume that I have 2.5.3
>
> Pozdrawiam
>
> Piotr Olszewski
>
> -----Original Message-----
> From: firebird-support@yahoogroups.com
> [mailto:firebird-support@yahoogroups.com]
> Sent: Tuesday, March 29, 2016 11:45 AM
> To: firebird-support@yahoogroups.com
> Subject: Re: [firebird-support] How to add previous column value to current
> value?
>
> 29.03.2016 11:40, 'Piotr Olszewski' piotr.olszewski@...
> [firebird-support] wrote:
>> I need to get a date difference (days between) between rows.
>
> With Firebird 3.0 you can use window function LAG.
>
> --
> WBR, SD.
>
>
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> Visit http://www.firebirdsql.org and click the Documentation item on the
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> Yahoo Groups Links
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> ------------------------------------
> Posted by: "Piotr Olszewski" <piotr.olszewski@...>
> ------------------------------------
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Visit http://www.firebirdsql.org and click the Documentation item
> on the main (top) menu. Try FAQ and other links from the left-side menu there.
>
> Also search the knowledgebases at http://www.ibphoenix.com/resources/documents/
>
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> ------------------------------------
>
> Yahoo Groups Links
>
>
>