RE: trouble with sql
- From: "Boyle, Christopher" <Christopher.Boyle@xxxxxxxxxxxxx>
- To: <chris_stephens@xxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 3 Jan 2007 16:32:36 -0500
Okay, this might have a better explain plan (assuming 9i or above)
with ps2 as ( select/*+ materialize */ p.periodID, ps.projectNumber,
max(ps.changeDate) as changeDate
from period p, projectStatus ps
where ps.changeDate >= trunc( p.startDate )
and trunc( ps.changeDate ) <= p.endDate
group by p.periodID, ps.projectNumber )
select ps2.periodID, ps2.projectNumber, ps2.changeDate, ps3.statusID
from ps2, projectStatus ps3
where ps2.projectNumber = ps3.projectNumber and ps2.changeDate =
ps3.changeDate;
but I cant tell without table definitions. Can a project have more than
one active status? From the query I would guess that the max change
date indicates the current status but I am not sure. Can periods
overlap?
Chris
_____
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Stephens, Chris
Sent: Wednesday, January 03, 2007 3:34 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: trouble with sql
There has got to be a way to do this but I can't find the syntax.
Essentially I need the max of column 3 grouped by column 1 and 2 and
also the value of column 4 that corresponds to the returned columns 1,2,
and 3.
Here is the actual sql that I believe to be using an unnecessary join:
select ps2.periodID, ps2.projectNumber, ps2.changeDate, ps3.statusID
from ( select p.periodID, ps.projectNumber, max(ps.changeDate) as
changeDate
from period p, projectStatus ps
where ps.changeDate >= trunc( p.startDate )
and trunc( ps.changeDate ) <= p.endDate
group by p.periodID, ps.projectNumber ) ps2, projectStatus ps3
where ps2.projectNumber = ps3.projectNumber and ps2.changeDate =
ps3.changeDate
Is there a better way to write this?
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