as mysql_auth is not safe, please use pam_mysql instead!
Example:

squid.conf
auth_param basic program /usr/lib/squid3/pam_auth
auth_param basic children 5
auth_param basic credentialsttl 1 hour
auth_param basic casesensitive on

/etc/pam.d/squid
auth       required     pam_mysql.so user=USER passwd=PASSWD host=/var/run/mysqld/mysqld.sock db=DBNAME table=account usercolumn=account_id passwdcolumn=password [where=account_type_fkey != 1 AND account_type_fkey != 6]
account    required     pam_mysql.so user=USER passwd=PASSWD host=/var/run/mysqld/mysqld.sock db=DBNAME table=account usercolumn=account_id passwdcolumn=password [where=account_type_fkey != 1 AND account_type_fkey != 6]

Here is a simple patch for mysql_auth v0.8, a Squid HTTP proxy MySQL authentication module by Ervin Hegedus. Autodesk Algor Simulation Professional 2011 oem Autodesk AutoCAD Civil 3D 2011oem
The patch enables the user to configure a additional part for the select-statement like 'is_active = 1'.
 
The patch may be downloaded from here!
 
You can apply the patch like this:

wget http://people.arxnet.hu/airween/mysql_auth/mysql_auth-0.8.tar.gz
tar xvzf mysql_auth-0.8.tar.gz
wget http://www.zero-sys.net/portal/download/additionalselect.patch
cd mysql_auth-0.8
patch -p1 < ../additionalselect.patch

buy Autodesk Algor Simulation Professional 2011oem buy Autodesk AutoCAD Civil 3D 2011 oem More details on how to use mysql_auth can be found at the homepage of mysql_auth