Postgresql Random Rec Set - no Duplicates with Livecode
Rick Harrison
harrison at all-auctions.com
Wed Feb 2 21:41:54 EST 2011
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
>
> Le 2 févr. 2011 à 23:40, Rick Harrison a écrit :
>
>> Hi Pierre,
>>
>> What I'm looking to do is to perform the Random pick from the database,
>> not reorder my results randomly after I've gotten all records. I don't think
>> the code links below help me to do that. I've been down this road already.
>>
>> Thanks anyways!
>>
>> Rick
>>
>> On Feb 2, 2011, at 4:29 PM, Pierre Sahores wrote:
>>
>>> It's a SQL syntax task, not a revDB one and as soon as the query will be OK, revDB will just handle it as expected.
>>>
>>> <http://archives.postgresql.org/pgsql-general/2007-08/msg02034.php>
>>> <http://bytes.com/topic/postgresql/answers/857541-random-sample-rows>
>>>
>>> Best regards,
>>>
>>> Le 2 févr. 2011 à 21:29, Rick Harrison a écrit :
>>>
>>>> Hi there,
>>>>
>>>> I need to know the best way to get a random subset
>>>> of records without duplicates in the resulting record
>>>> set using a Postgresql database query with Livecode
>>>> on On-Rev.
>>>>
>>>> In other words, I don't want to have to get all of the
>>>> records in the database first just to be able to pick
>>>> out the 21 random records i need, as that seems rather
>>>> inefficient. Assume a couple of thousand records
>>>> in the database or more.
>>>>
>>>> Thanks for your ideas in advance!
>>>>
>>>> Rick
>>>>
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