Date: Mon, 19 Nov 2018 17:20:23 +0100 (CET)
From: Andreas Joseph Krogh <andreas@visena.com>
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: pgsql-sql <pgsql-sql@lists.postgresql.org>
Message-ID: <VisenaEmail.4c.51bde41e996a86d1.1672cc0ac94@tc7-visena>
In-Reply-To: 
 <CAKFQuwZjrGG5gtakGN7QMCgCZYYVcCUwXAWmvqdxvi_DbuK8Vw@mail.gmail.com>
Subject: Sv: Re: Difficulties with LAG-function when calculating overtime
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P=C3=A5 mandag 19. november 2018 kl. 17:08:57, skrev David G. Johnston <
david.g.johnston@gmail.com <mailto:david.g.johnston@gmail.com>>:
On Mon, Nov 19, 2018 at 6:24 AM Andreas Joseph Krogh <andreas@visena.com=20
<mailto:andreas@visena.com>> wrote:
Anyone has a clever way to solve this kinds of issues and craft a query whi=
ch=20
produces the desired result as in the table above?
=C2=A0
Thinking in terms of theory - you need to calculate the first row and then=
=20
calculate the next row using data from the first row.=C2=A0 Then calculate =
the third=20
row using data from the second row (you might need to carry-forward some va=
lue=20
from the first row so that the third row can see them...).=C2=A0 That sound=
s like=20
the algorithm for iteration which is implemented in SQL via "WITH RECURSIVE=
".
=C2=A0
David J.


=C2=A0
Yea, I kind of figured RECURSIVE CTE was the way foreward...
If anyone has got this working, give me a tip:-)
=C2=A0
-- Andreas Joseph Krogh


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<div>P=C3=A5 mandag 19. november 2018 kl. 17:08:57, skrev David G. Johnston=
 &lt;<a href=3D"mailto:david.g.johnston@gmail.com">david.g.johnston@gmail.c=
om</a>&gt;:</div>

<blockquote style=3D"border-left: 1px solid rgb(204, 204, 204); margin: 0pt=
 0pt 0pt 0.8ex; padding-left: 1ex;">
<div dir=3D"ltr">
<div class=3D"gmail_default" style=3D"font-family:arial,helvetica,sans-seri=
f"><span style=3D"font-family:Arial,Helvetica,sans-serif">On Mon, Nov 19, 2=
018 at 6:24 AM Andreas Joseph Krogh &lt;<a href=3D"mailto:andreas@visena.co=
m">andreas@visena.com</a>&gt; wrote:</span></div>

<div class=3D"gmail_quote">
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">
<div>Anyone has a clever way to solve this kinds of issues and craft a quer=
y which produces the desired result as in the table above?</div>
</blockquote>

<div>=C2=A0</div>

<div class=3D"gmail_default" style=3D"font-family:arial,helvetica,sans-seri=
f">Thinking in terms of theory - you need to calculate the first row and th=
en calculate the next row using data from the first row.=C2=A0 Then calcula=
te the third row using data from the second row (you might need to carry-fo=
rward some value from the first row so that the third row can see them...).=
=C2=A0 That sounds like the algorithm for iteration which is implemented in=
 SQL via &quot;WITH RECURSIVE&quot;.</div>

<div class=3D"gmail_default" style=3D"font-family:arial,helvetica,sans-seri=
f">=C2=A0</div>

<div class=3D"gmail_default" style=3D"font-family:arial,helvetica,sans-seri=
f">David J.</div>
</div>
</div>
</blockquote>

<div>=C2=A0</div>

<div>Yea, I kind of figured RECURSIVE CTE was the way foreward...</div>

<div>If anyone has got this working, give me a tip:-)</div>

<div>=C2=A0</div>

<div class=3D"visena-email-signature" data-visena-message-id=3D"&lt;VisenaE=
mail.4c.51bde41e996a86d1.1672cc0ac94@tc7-visena>">
<div>--
<div><span style=3D"font-family:arial,helvetica,sans-serif;"><strong>Andrea=
s Joseph Krogh</strong></span></div>
</div>
</div>
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