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| Use of 'DISTINCT' keyword |
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| javaforvivek |
 Posted: Fri Aug 13, 2004 5:03 am Post subject: Use of 'DISTINCT' keyword |
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Master
Joined: 14 Jun 2002
Posts: 282
Location: Pune,India
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Hi,
WBIMB5 + CSD3
I want to know whether anybody has used 'DISTINCT' keyword.
The ESQL documentation says that it does not support SELECT DISTINCT clause as in normal SQL, nor it specifies what's the use of 'DISTINCT' keyword.
I have an XML Message like this:
<File>
<Line>
<DocNumber>1</DocNumber>
---some more details
</Line>
<Line>
<DocNumber>1</DocNumber>
---some more details
</Line>
<Line>
<DocNumber>2</DocNumber>
---some more details
</Line>
</File>
AS we can see, that document number 1 is repeated in two <Line> tags.
What I want to do is, get the Distinct Document Numbers from the message, i.e. my select statement should give me 1 and 2 rather than 1,1 and 2.
Whether we can write such Select statement or not?
I know that I can write some turn-around code, like storing document numbers in Environment.variable.temp[] and then removing the duplicate entries.
_________________
Vivek
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...when you have eliminated the impossible, whatever remains, however improbable, must be the truth. |
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| jefflowrey |
| Posted: Fri Aug 13, 2004 5:29 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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If the documentation says that DISTINCT is not supported, then DISTINCT is not supported and you will have to do something else.
It's a shame that there isn't an ORDER BY either. That would make it a little easier.
_________________
I am *not* the model of the modern major general. |
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| PGoodhart |
| Posted: Fri Aug 13, 2004 6:26 am Post subject: |
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Master
Joined: 17 Jun 2004
Posts: 278
Location: Harrisburg PA
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This strikes me as the sort of thing that someone ought to raise as a formal requirement through IBM...
I agree that the distinct keyword and order by clause are very useful and I can't think of a good reason not to allow them? Is it because these are extensions to standard SQL and they are the same on all the database platforms?
_________________
Patrick Goodhart
MQ Admin/Web Developer/Consultant
WebSphere Application Server Admin |
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| javaforvivek |
| Posted: Fri Aug 13, 2004 8:37 am Post subject: |
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Master
Joined: 14 Jun 2002
Posts: 282
Location: Pune,India
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I agree with both of you, but then I wonder what is the use of DISTINCT keyword??
Or it's just kept as a Reserved keyword for the future releases when the Distinct functionality will be implemented in ESQL...
_________________
Vivek
------------------------------------------------------
...when you have eliminated the impossible, whatever remains, however improbable, must be the truth. |
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| martinrydman |
| Posted: Fri Aug 13, 2004 10:17 am Post subject: |
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Centurion
Joined: 30 Jan 2004
Posts: 139
Location: Gothenburg, Sweden
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Hi,
I'd only like to point out that, as long as you're accessing a datbase, you can use the PASSTHRU command, which allows you to use the full range of SQL supported by the target database. If you're using ESQL to access message trees, then you're stuck with what ESQL has to offer.
/Martin |
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