title: subquery using IN clause
body: <pre><code>----------
  User
  ----------
  user_ID(pk)
  UserEmail
  
  ----------
  Employer1
  ----------
  Emp1ID(pk)
  Emp1NO
  
  ----------
  Employer2
  ----------
  Emp2ID(pk)
  Emp2NO
  
  ----------
  Project
  ----------
  ProjEmpID
  ProjEmpMGRID
  </code></pre>
  
  <p>I need to display User Email ID. The relation between the table goes like this:
  In the Employer(1&amp;2) table EmpID contains the value of UserID in the User table.</p>
  
  <p>the Employer No relates to the values from the Project table.
  EmpNo contains values from ProjEmpID, ProjEmpMGRID. </p>
  
  <pre><code> select u.user_email from users u, Employer emp 
      where emp.Emp1ID =  u.user_id and 
      emp.Emp1NO IN
      (select ProjEmpID,ProjEmpMGRID from project)
  union 
    select u.user_email from users u, Employer emp 
      where emp.Emp2ID =  u.user_id and 
      emp.Emp2NO IN
      (select ProjEmpID,ProjEmpMGRID from project)
  </code></pre>
  
  <p>but i get error in the subquery stating too many parameters on the IN clause.Is there any other way i could rewrite the query to get result. any help would be appreciated. </p>