php - Sorting a list from MySQL alphabetically using two tables for input data -

i have following php:

<?php $con = mysql_connect("localhost","foo","bar"); if (!$con) {     die('could not connect: ' . mysql_error()); }  mysql_select_db("zed", $con); $gettagid = $_get["id"]; //make loop outputs each coupon has been tagged  $alphatagsql = mysql_query("select * coupon_tags tagid = '$gettagid'");  $alphatagsqlarr[] = mysql_fetch_array($alphatagsql);  foreach($alphatagsqlarr $mouse)     {         $nzed = $mouse["couponid"];         $brah = mysql_query("select * coupons couponid = '$nzed'");         $pen[] = mysql_fetch_row($brah);     }  foreach($pen $ruler)     {         echo $pen;     }  ?> 

what i'm trying select tagid $_get, match of couponid's match in table coupon_tags, match coupon_id's retailername in table coupons, couponid match field id. want list them alphabetically. i'm running few problems - namely, error warning: mysql_fetch_row(): supplied argument not valid mysql result resource.

any help?

try change

$brah = mysql_query("select * coupons couponid = '$nzed'");  

into

$brah = mysql_query("select * coupons couponid = '$nzed'") or die(mysql_error()); 

it give more information on why query didn't succeed.