Jump to content

rand() always returns the same..


w0rtel

Recommended Posts

I want to get a random row from my table. And i use this:

 


$sql = "SELECT * FROM random ORDER BY RAND() LIMIT 1";



$result = mysql_query($sql);

$object = mysql_fetch_object($result);



$rid = $object->rid;

But I always get the first row. Never a different one.. Why?

 

(MySQL v. MySQL 3.23.54-nt)

 

Thnx 4 the help..

Link to comment
Share on other sites

I want to get a random row from my table. And i use this:

 


$sql = "SELECT * FROM random ORDER BY RAND() LIMIT 1";



$result = mysql_query($sql);

$object = mysql_fetch_object($result);



$rid = $object->rid;

But I always get the first row. Never a different one.. Why?

 

(MySQL v. MySQL 3.23.54-nt)

 

Thnx 4 the help..

 

Probably because you\'re opening a new connection each time.. The rand() function is not truly random, so you need to give it a near random seed, i.e. use rand(seedvalue)...

 

You may use something like rand(seconds(curdat())) or some other stuff. If you\'re using php you could take a variable and assign a random number to it and them use that as seed in you query.

 

P., denmark

Link to comment
Share on other sites

  • 1 month later...

may be u can random selection by doing that:

get the last record from table ( u can do that \"select last_insert_id()\" )

then $min=1 ; $max=$last_record_id ;

$random_record=rand($min,$max);

then u print the random row by mysql_fetch_row..

if u have 10000 records in your table it will search all the records from table then randomize 1 row. searching is too late. but doing like this searching is quite time and it is easy for me :)

see u later

Cihan

Link to comment
Share on other sites

  • 2 weeks later...

thanks to the information above I managed to get a good solution:

 

[php:1:d09dd98aa6]<?php

$random_seed=rand(1, time());

$query = \"SELECT * FROM $table ORDER BY RAND($random_seed) limit 1\";

?>[/php:1:d09dd98aa6]

 

Thanks all.

- Dave

Link to comment
Share on other sites

  • 7 years later...

thanks to the information above I managed to get a good solution:

 

[php:1:d09dd98aa6]<?php

$random_seed=rand(1, time());

$query = \"SELECT * FROM $table ORDER BY RAND($random_seed) limit 1\";

?>[/php:1:d09dd98aa6]

 

Thanks all.

- Dave

 

What if the rand output doesnot equal row value.. It may produce 100 when u have 30 results only...

Link to comment
Share on other sites

This thread is more than a year old. Please don't revive it unless you have something important to add.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.