Error in SQL syntax - php

Question

I am getting this error , Not able to make out what is going wrong , please help.
A Database Error Occurred
Error Number: 1064
You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near ')' at line 1
SELECT GROUP_CONCAT(DISTINCT ud.userid) as id from pr_users_details ud INNER JOIN pr_users u ON ud.userid = u.id WHERE ud.status = '1' AND ()
My function looks like this:
function get_nomination_emailids($functions, $levels, $roles, $locations, $emails)
{
$SQL.="SELECT GROUP_CONCAT(DISTINCT ud.userid) as id from pr_users_details ud INNER JOIN pr_users u ON ud.userid = u.id WHERE ud.status = '1' ";
if(count($functions)>0)
{
$d = implode(",",$functions);
$whereand[] = " u.departmentid IN (".$d.") ";
}
if(count($levels)>0)
{
$d1 = implode(",",$levels);
$whereand[] = " ud.designation_id IN (".$d1.") ";
}
if(count($roles)>0)
{
$d2 = implode(",",$roles);
$whereand[] = " u.userroleid IN (".$d2.") ";
}
if(count($locations)>0)
{
$d3 = implode(",",$locations);
$whereand[] = " u.branchid IN (".$d3.") ";
}
if(count($emails)>0)
{
$d4 = implode(",",$emails);
$whereor[] = " ud.userid IN (".$d4.") ";
}
$whr = array();
if(isset($whereand))
$whr[] = " (".implode(" AND ",$whereand).") ";
if(isset($whereor))
$whr[] = " (".implode(" OR ",$whereor).") ";
if(count($whr > 0))
{
$SQL .= " AND (".implode(" OR ",$whr).") ";
}
$query = $this->db->query($SQL);
$return = $query->result_array();
return $return[0]['id'];
//print_r($return);die;
}

Answer 1

AND() remove in your query try this.
SELECT GROUP_CONCAT(DISTINCT ud.userid) as id from pr_users_details ud INNER JOIN pr_users u ON ud.userid = u.id WHERE ud.status = '1'