title: How to create a query to compare two exact results of two additional queries?
body: <p>I´m creating a data model to register the SERVICES that an EMPLOYEE is able to perform based on its list of COURSES completed (COURSE_ID). To do this I have two data tables: EMPLOYEES and SERVICES. And I have two map tables: one table to relate the COURSES completed by EMPLOYEE and another table to relate the COURSES required by a SERVICE.</p>
  
  <p>The data tables looks like this:</p>
  
  <p>EMPLOYEES:</p>
  
  <pre><code>EMP_ID   NAME
  =============
  1        Joe
  2        Bob
  3        Rob
  </code></pre>
  
  <p>SERVICES:</p>
  
  <pre><code>SERV_ID   SERVICE
  ====================
  1         Install
  2         Configure
  3         Manage
  </code></pre>
  
  <p>The relation or map tables look like this:</p>
  
  <p>EMPLOYEE_COURSES</p>
  
  <pre><code>EMP_ID   COURSE_ID
  ==================
  1        3
  1        5
  1        6
  2        5
  3        4
  </code></pre>
  
  <p>SERVICE_COURSES</p>
  
  <pre><code>SERV_ID  COURSE_ID
  ==================
  1        3
  1        5
  1        6
  2        3
  3        4
  </code></pre>
  
  <p>The query result that I want to produce should look like this where only SERVICES 1 and 3 are shown since only two EMPLOYEES have the required courses by SERVICE:</p>
  
  <pre><code>SERV_ID  EMP_ID  SERVICE    NAME
  ================================
  1        1       Install    Joe
  2        1       Configure  Joe
  3        3       Manage     Rob
  </code></pre>
  
  <p>Any help is appreciate.
  Thanks !</p>