RE: What does LIKE %% actually do in a WHERE clause?

From: Dunbar, Norman (Capgemini) <>
Date: Fri, 7 Oct 2011 06:40:35 +0000
Message-ID: <341078561D12A54D8FEA365F2489FD27FE0F_at_EATOLEXMBS01.PRODDS.NTNL>

Morning Randolf,

>> I should have added that if you don't use an explicit ORDER
>> BY clause with top N queries like below your result set
>> isn't deterministic.

Yes, that's not a problem in this case - I'm told.

>> ...

>> There are cases where the order really doesn't matter but it
>> is a common misconception therefore I mention it here.
No worries, I am aware of it though. This is something that the developer/users can run via a front end to the application, so they are doing what they want to do.  

>> ...

>> Using the ROWNUM at the same level as the ORDER BY is again
>> a common misconception because it will not do what it seems
>> to express - it will first retrieve the first N random rows
>> and order them afterwards.

This I know to be true - from past experience! ;-)

>> Hope this helps,

As ever, I'm grateful for all input. Thanks.


Norman Dunbar
Contract Senior Oracle DBA
Capgemini Database Build Team
Internal : 7 28 2051
External : 0113 231 2051

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Received on Fri Oct 07 2011 - 01:40:35 CDT

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