title: Join three tables and display in gridview as per condition
body: <p>In my Access database I am trying to display data from three tables:</p>
  
  <ol>
  <li>PERS</li>
  <li>COURSE</li>
  <li>WORKED</li>
  </ol>
  
  <p>I want all rows from <code>PERS</code> and some matching fields from <code>COURSE</code> and <code>WORKED</code>. <code>KNO</code> is the common field in all tables</p>
  
  <p>eg : SELECT [KNO], [Name], [Company], [Location], [State] FROM [Pers]</p>
  
  <pre><code>  If the KNo had done CCNA (Course.Qualification)
  
    if he had Worked in Channai or Kolkatta or in Bangalore (Worked.Coyloc)
  </code></pre>
  
  <p>then only show</p>
  
  <p>I used : </p>
  
  <pre><code>Select 
       Pers.KNO, Pers.Name, Pers.Company, Pers.Location, Pers.State 
  from Pers 
  left join (Course on pers.KNo=Course.KNO) 
  left join Worked.KNo=Per.KNO 
  where 
       Course.Qualification='CCNA' 
      and (Worked.Coyloc='Bangalore' or Worked.Coyloc='Channai or Worked.Coyloc='Kolkatta')
  </code></pre>
  
  <p>I am having trouble adding the [Worked] table to the query. When I just include [Pers] and [Course] I get the results I expect.</p>
  
  <pre><code>Select 
     Pers.KNO, Pers.Name, Pers.Company, Pers.Location, Pers.State 
  from Pers 
  left join Course 
     on pers.KNo=Course.KNO 
  where 
       Course.Qualification='CCNA'
  </code></pre>