Postgresql Random Rec Set - no Duplicates with Livecode

Pierre Sahores psahores at free.fr
Thu Feb 3 02:17:22 EST 2011


'Morning Rick,

To avoid possible border effects, did you try how it goes in adding the distinct clause alike this :

SELECT DISTINCT *
FROM table
WHERE condition = true
ORDER BY hashfloat8(random())
LIMIT 10;

Best,

Pierre


Le 3 févr. 2011 à 04:06, Rick Harrison a écrit :

> Hi yet again Pierre,
> 
> Ok, I did a test where I used the limit of 48 out of 49 records.
> It didn't pick even one duplicate.  Hurray!!!  The code must
> advance the record counter randomly so no duplicates
> occur.  Nice, but unexpected.
> 
> Ok, all is well now.
> 
> Thanks again,
> 
> Rick
> 
> On Feb 2, 2011, at 9:41 PM, Rick Harrison wrote:
> 
>> Hi again Pierre,
>> 
>> How do I avoid picking duplicates though?
>> 
>> Rick
>> 
>> On Feb 2, 2011, at 6:09 PM, Pierre Sahores wrote:
>> 
>>> Hi Rick,
>>> 
>>> SELECT *
>>> FROM table
>>> WHERE condition = true
>>> ORDER BY hashfloat8(random())
>>> LIMIT 10;
>>> 
>>> Are you sure that the order by + limit clauses used together can't suit exactly your needs ?
>>> 
>>> Best,
>>> 
>>> Pierre
> 
> 
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--
Pierre Sahores
mobile : (33) 6 03 95 77 70

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