Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!usc!apple!mrspoc!itkin
From: itkin@mrspoc.Transact.COM (Steven M. List)
Newsgroups: comp.databases
Subject: Re: How to change each row in a table using SQL ?
Message-ID: <1990Oct26.164754.3136@mrspoc.Transact.COM>
Date: 26 Oct 90 16:47:54 GMT
References: <1990Oct25.081639.14155@abblund.se>
Reply-To: itkin@guinan.Transact.COM
Organization: Transact Software, Inc., Los Altos, CA
Lines: 26

erik@abblund.se (Erik Sparre) writes:

>The user entered 900 rows into table. Instead of entering the elapsed time
>in hours and minutes he entered the wall clock time of completion.
>(The system registers flying times for aeroplanes)
>I have the start wall clock time, so it seems possible to recalculate the
>erroneous field with a simple expression like:

>for each row do
> elapsed_time := elapsed_time - start_time

>example:
> Start time was 12:32 and landing time was 13:45.
> The elapsed time should be 1:13, but was entered as 13:45

Unless I'm missing something painfully obvious, shouldn't this just be

    update <table>
        set elapsed_time to elapsed_time - start_time;

Hmm?
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