Most efficient way to return a random specific sample size in sql / coldfusion -

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i need return values based on sample size. if user selects 5% query resulting in random 5% of rows origonal query. there way can achieve sql?

currently process run query generate random numbers remove rows until 5% left, build new query off rows left. not believe efficient way, better ideas?

thanks

what end? support out of box, eg. sql server limiting result sets using tablesample:

select firstname, lastname person.person  tablesample (5 percent) ;

in system should try filter on server, not on client. eg. use mysqls crc32 compute row checksum , use checksum qualify 5% rows. or use rand() similar effect. whatever do, don't fetch entire table , filter rows on client.


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