title: SQL: Proper JOIN Protocol
body: <p>I have the following tables with the following attributes:</p>
  
  <pre><code>Op(OpNo, OpName, Date)
  OpConvert(OpNo, M_OpNo, Source_ID, Date)
  Source(Source_ID, Source_Name, Date)
  Fleet(OpNo, S_No, Date)
  </code></pre>
  
  <p>I have the current multiple JOIN query which gives me the results that I want:</p>
  
  <pre><code>SELECT O.OpNo AS Op_NO, O.OpName, O.Date AS Date_Entered, C.* 
  FROM Op O
  LEFT OUTER JOIN OpConvert C
  ON O.OpNo = C.OpNo 
  LEFT OUTER JOIN Source D
  ON C.Source_ID = D.Source_ID
  WHERE C.OpNo IS NOT NULL
  </code></pre>
  
  <p>The problem is this.  I need to join the Fleet table on the previous multiple JOIN statement to attach the relevant S_No to the multiple JOIN table.  Would I still be able to accomplish this using a LEFT OUTER JOIN or would I have to use a different JOIN statement?  Also, which table would I JOIN on?  </p>
  
  <p>Please note that I am only familiar with LEFT OUTER JOINS.</p>
  
  <p>Thanks. </p>