| indexing nulls [message #635872] |
Fri, 10 April 2015 05:36  |
orausern
Messages: 826
Registered: December 2005
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Senior Member |
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Hi Experts,
I have a question on indexing the nulls. I have a table where a column is nullable and the query is find the data where the column "IS NOT NULL'.
I was reading on this topic and saw this reference:
http://www.dba-oracle.com/oracle_tips_null_idx.htm
where it is said:
Quote:
Note: Starting in Oracle 11g, there is new "create index" syntax that allows NULL values to be included in the index:
create index
emp_ename_idx
on
emp
(ename asc, 1)
;
Here, the "1" tells Oracle that to index on NULL values within the tables.
I find this to be useful but when I refer to the oracle documentation of Oracle 11g, I don't see it documented. Can someone help to confirm if this is a valid fact that by adding '1' oracle will allow the null value to be indexed?
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| Re: indexing nulls [message #635892 is a reply to message #635891] |
Fri, 10 April 2015 10:38  |
orausern
Messages: 826
Registered: December 2005
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Senior Member |
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Thank you experts! Thanks a lot Lalit!! That blog from Tom Kyte cleared up everything. I was able to test as well and my question is resolved.
Thank you!
OrauserN
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| Re: indexing nulls [message #635896 is a reply to message #635892] |
Fri, 10 April 2015 11:24 |
Lalit Kumar B
Messages: 3174
Registered: May 2013
Location: World Wide on the Web
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Senior Member |
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Sooner or later you will understand that not everything that comes up on top Google search is actually good. Burleson's site is one such example.
And, I have a strong feeling that the content is just copy pasted without any citation. I find that site useless and just a means to advertise and be on top of search engines. Simple copy pasting content, exaggerated output, guicy title, and there you go... Bu**sh**
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