MYSQL SELECT查询不起作用

I want to select email address from DB to send a email. Following is my query that I have made.

$userID=$_SESSION['userID'];

$select_query = mysql_query("SELECT * FROM employee WHERE emp_id = '$userID'");
$select_sql = mysql_fetch_array($select_query);
$name=$select_sql['manager_name'];

$select_query1 = mysql_query("SELECT email FROM employee WHERE employee.name='$name'");
$select_sql1 = mysql_fetch_array($select_query1);
$email=$select_sql1['email'];

But $select_query1 return "NULL Invalid address:" instead of the correct value. I could not found the problem with this. Please help !

You are using $_SESSION['userID'] to get all data from table employee so instead of doing two queries simply try this

 $empID = $_SESSION['userID'];
 $query = mysql_query("SELECT * FROM employee WHERE emp_id=$empID");
 $result = mysql_fetch_array($query);
 $email = $result['email'];