Thread: Best way to return Random rows from a table with non-repeatability of rows

Dear folks,

I have a table with thousands of rows ( currently 15 thousand but will grow very fast).
I need to return from the query rows which are random and non-repeating. 
 I know there is random() function, but would like to know from postgresql practitioners before embarking that path.
Please let me know what is best way to handle this type of queries.

regards
Kiran


> Dear folks,
>
> I have a table with thousands of rows ( currently 15 thousand but will grow very fast).
> I need to return from the query rows which are random and non-repeating.
>  I know there is random() function, but would like to know from postgresql practitioners before embarking that path.
> Please let me know what is best way to handle this type of queries.
>
> regards
> Kiran

Hi,

if you're using Postgres >= 9.5 what you are looking for is TABLESAMPLE.

Syntax is here:
https://www.postgresql.org/docs/9.5/static/sql-select.html

Google tablesample+postgres to get some examples on how to use it.

Bye,
Chris.




Hi Chris,

Thank you very much. Will look into examples and syntax.

regards
Kiran


On Sat, Oct 29, 2016 at 3:18 PM, Chris Mair <chris@1006.org> wrote:
Dear folks,

I have a table with thousands of rows ( currently 15 thousand but will grow very fast).
I need to return from the query rows which are random and non-repeating.
 I know there is random() function, but would like to know from postgresql practitioners before embarking that path.
Please let me know what is best way to handle this type of queries.

regards
Kiran

Hi,

if you're using Postgres >= 9.5 what you are looking for is TABLESAMPLE.

Syntax is here:
https://www.postgresql.org/docs/9.5/static/sql-select.html

Google tablesample+postgres to get some examples on how to use it.

Bye,
Chris.