Re: Randomly select 5 records from a db

ORDER BY RAND() is supported in MySQL 3.23 and later. So to get what you are looking for: SELECT * FROM meminfo WHERE type='bene' ORDER BY RAND() LIMIT 5; Maxim Maletsky wrote: > > This is what I used ( when I had the exactly same question ) : > > function rand_num_array($count) > { > $stand_a = array(); > $rand_a = array(); > > for( $i = 0; $i < $count; $i++ ) > $stand_a[$i] = $i; > > $rand_max = $count; > for( $i = 0; $i < $count; $i++ ) > { > $rand_index = rand(0, $rand_max); > if( $rand_index == $rand_max ) > $rand_index = $rand_max - 1; > $rand_a[$i] = $stand_a[$rand_index]; > for( $j = $rand_index; $j < $rand_max - 1; $j++ ) > $stand_a[$j] = $stand_a[$j + 1]; > > $rand_max--; > } > > return $rand_a; > } > > And in your connection: > > if(!$id || !isset($array_ra)) > { > $array_ra = array(); > $array_ra = rand_num_array($v_mysql->Num); > } > > while( list($rand_key, $rand_val) = each($array_ra)) > { > $v_mysql->seek( $rand_val ); > $v_mysql->fetch_record(); > ..... > } > > Sorry I use a class for the mysql database, but I hope you will figure out > how to change it into "your way" > The $array_ra is registered by sessions, so in case you do something on the > page and it has to be refreshed > your data will not be resorted again. It is sorted randomly only in case you > access it for the first time (makes no sense to do it twice) > > Id is assigned only when someone selects a record, so also in this case the > data remains in order you saw it first time. > > See www.j-door.com/experts.html to understand what I am talking about, > refresh the staff few times and see the differences. > > Cheers!! > > P.S: my need for random sorting was that when we sale a place on our website > our clients often asked : "here will we be placed , on top or at the bottom? > " So I decided to answer: "It will depend on your luck" > > -----Original Message----- > From: Ben Weinberger [mailto:ben@digitalsmiths.com] > Sent: Tuesday, October 03, 2000 7:11 AM > To: php-general@lists.php.net > Subject: [PHP] Randomly select 5 records from a db > > Hi~ > I am constructing part of a PHP4 page that I would like to randomly select > 5 records from my MySQL db and display them. I know how to do the standard > selects and display the data, but nothing random. The database lists > benefits of being a member of our association, and we would like to display > different ones each time the query is performed-- is there a way to > randomly query the db for 5 records? > > I tried using the following but it didn't work.... > > $sql= "SELECT * from meminfo where type='bene'"; > $result= mysql_query($sql); > > while ($myrow= mysql_fetch_array($result)) { > $benefits=$myrow["title"]; > print "$benefits<BR>"; //this is just to test to make sure it's pulling > the > data I want > > srand ((double) microtime() * 10000000); > $input = array ("$benefits", 5); > $rand_keys = array_rand ($input); > print $input[$rand_keys[0]]."\n"; > print $input[$rand_keys[2]]."\n"; > print $input[$rand_keys[3]]."\n"; > print $input[$rand_keys[4]]."\n"; > print $input[$rand_keys[5]]."\n"; > } > > Thanks, > -Ben > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, e-mail: php-general-unsubscribe@lists.php.net > For additional commands, e-mail: php-general-help@lists.php.net > To contact the list administrators, e-mail: php-list-admin@lists.php.net > > ------------------------------------------------------------------------ > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, e-mail: php-general-unsubscribe@lists.php.net > For additional commands, e-mail: php-general-help@lists.php.net > To contact the list administrators, e-mail: php-list-admin@lists.php.net