title: 2 Outer Joins on Same Table?
body: <p>Here is a question which has been boggling me for few days now, and I searched and searched but couldn't find any convincing answer !</p>
  
  <p>Simple question, why is it restricted to have 2 Outer Joins in SQL, on same table even with different columns being used, check the queries below for better understanding. Also I can overcome them using nested sub query or ANSI joins, but then why it is even restricted in the first place using (+) operator!</p>
  
  <p>In this question I'm referring to the error : </p>
  
  <blockquote>
    <p>ORA-01417: a table may be outer joined to at most one other table</p>
  </blockquote>
  
  <p>What I want to ask is why this is allowed :</p>
  
  <pre><code>select * from
  a, b, c
  where a.a1 = b.b1
  and a.a2 = c.c1
  </code></pre>
  
  <p>And why this is not allowed:</p>
  
  <pre><code>select * from
  a, b, c
  where a.a1(+) = b.b1
  and a.a2(+) = c.c1
  </code></pre>
  
  <p>Please leave ANSI and Nested SubQueries alone</p>