Information Systems
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Igor Tandetnik [itandet...@mvps.org]
Sent: Monday, October 17, 2011 10:06 AM
To: sqlite-users@sqlite.org
Subject: EXT :Re: [sqlite] "is not null" and index
On 10/17/2011 9:30 AM, Blac
On 10/17/2011 9:30 AM, Black, Michael (IS) wrote:
According to this benchmark the break-even point is at 40% nulls. I asssume
you have a different test?
I did mention "rule of thumb". Specific cases may vary. I must admit I'm
too lazy to build tests for someone else's problem.
The fact
rop Grumman Information Systems
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Igor Tandetnik [itandet...@mvps.org]
Sent: Monday, October 17, 2011 8:14 AM
To: sqlite-users@sqlite.org
Subject: EXT :Re: [sqlite] "is not
On Mon, Oct 17, 2011 at 9:14 AM, Igor Tandetnik wrote:
> Jean-Christophe Deschamps wrote:
> >>> How can indexes be used with "not null" queries?
> >>
> >> They cannot.
> >
> > If one sees NOT NULL as the complement of NULL, i.e. values in the
> > range
Jean-Christophe Deschamps wrote:
>>> How can indexes be used with "not null" queries?
>>
>> They cannot.
>
> If one sees NOT NULL as the complement of NULL, i.e. values in the
> range {min_value, max_value} (min and max depending on the column
> expected content and type),
Yoav Apter wrote:
> I have the following table:
>
> CREATE TABLE x ('col1', 'col2', 'col3')
> Create col1index on x ('col1')
>
> When I run this query: "select * from x where col1 is null" I see
the index on x is used.
> When I run this query: "select * from x where col1
Black, Michael (IS) wrote:
> What does distinct do?
> sqlite> explain query plan select distinct (col1) from x where col1 is not
> null;
> sele order from deta
> -
> 0 0 0 SCAN TABLE x USING COVERING INDEX
Unit
Northrop Grumman Information Systems
From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Igor Tandetnik [itandet...@mvps.org]
Sent: Monday, October 17, 2011 6:56 AM
To: sqlite-users@sqlite.org
Subject: EXT :Re: [sqlite] "is not null" and index
Yoav Apter wrote:
> I have the following table:
>
> CREATE TABLE x ('col1', 'col2', 'col3')
> Create col1index on x ('col1')
>
> When I run this query: "select * from x where col1 is null" I see the index
> on x is used.
> When I run this query: "select * from x where
Hi
I have the following table:
CREATE TABLE x ('col1', 'col2', 'col3')
Create col1index on x ('col1')
When I run this query: "select * from x where col1 is null" I see the index on
x is used.
When I run this query: "select * from x where col1 is NOT null" I see the index
on x is not used.
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