avies [simon.james.dav...@gmail.com]
Sent: Thursday, March 08, 2012 8:47 AM
To: General Discussion of SQLite Database
Subject: EXT :Re: [sqlite] Efficient random sampling in a large table using
builtin functions.
On 8 March 2012 14:37, Black, Michael (IS) wrote:
> Glad to know thatcould that pos
lite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
> behalf of Simon Davies [simon.james.dav...@gmail.com]
> Sent: Thursday, March 08, 2012 8:33 AM
> To: General Discussion of SQLite Database
> Subject: EXT :Re: [sqlite] Efficient random sampling in a large table using
> b
] Efficient random sampling in a large table using
builtin functions.
On 8 March 2012 14:20, Black, Michael (IS) wrote:
> You don't say what language you are working in. IN C++ I would just declare
> a "set" and put random row numbers in it until I had enough. Then use that
&
On 8 March 2012 14:20, Black, Michael (IS) wrote:
> You don't say what language you are working in. IN C++ I would just declare
> a "set" and put random row numbers in it until I had enough. Then use that
> set to build the SQL.
>
> SQLite's random() doesn't have a seed function so you don't r
2 4:10 AM
To: General Discussion of SQLite Database
Subject: EXT :[sqlite] Efficient random sampling in a large table using builtin
functions.
I have a table with millions of records.
When I run a query with
ORDER BY random() LIMIT N;
the RANDOM() function is evaluated against all rows of my r
I have a table with millions of records.
When I run a query with
ORDER BY random() LIMIT N;
the RANDOM() function is evaluated against all rows of my result set,
then sorting occurs, and as a result the query is slow.
In this case the query could be rewritten as:
* Generate N, random, row
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