array_rand() question

kbc1

Hi ,

I have this query which collects images names (i.e. image1.jpg, image2.jpg etc) from a table and stores them into an array:

	
$sqlquery = "SELECT imagename FROM tblbannerimages ORDER BY id DESC";
	$dataresult = mysql_query($sqlquery);
	$bannercount = mysql_num_rows($dataresult);
	while ($bannernames[] = mysql_fetch_array($dataresult)) {
	}
	mysql_free_result($dataresult);

I would like to get a random 'imagename' from the array each time the function is run and display it in an image as such:

<img src="path/to/images/$imagename"> etc...

Can someone explain how I would do this using array_rand()?

Thanks

thorpe

Much more efficient to only retrieve one random image from your query.

 $sqlquery = "SELECT imagename FROM tblbannerimages ORDER BY RAND(id) LIMIT 1";

kbc1

but that just gets the first record each time when i run it..

thorpe

Sorry.... Should be.

$sqlquery = "SELECT imagename FROM tblbannerimages ORDER BY RAND() LIMIT 1";

laserlight

but that just gets the first record each time when i run it..

If you are having problems with RAND() from SQL, you could do:

$result = mysql_query("SELECT COUNT(id) FROM tblbannerimages");
$row_count = mysql_result($result, 0);
if ($row_count > 0) {
	$randnum = mt_rand(0, $row_count - 1);
	$result = mysql_query("SELECT imagename FROM tblbannerimages LIMIT $randnum, 1");
	echo mysql_result($result, 0);
} else {
	echo 'No rows retrieved';
}

If ORDER BY RAND() randomises the entire potential result set, this may actually be faster. On the other hand, this uses two queries, and we normally prefer to minimise I/O, especially since there is the possibility of a race condition happening between queries and changing the number of rows in the table.