title: SQL join eliminating repeated columns
body: <p>So I dispose of a few tables which were all generated out of a single, common one.</p>
  
  <p>Their schemas are as</p>
  
  <p><code>T1: A, B, C, M, N
   T2: A, B, J, M
   T3: A, C, M, P
  </code></p>
  
  <p>and the expected result is a joined version of all tables discarding the repeated values.</p>
  
  <p><code>R: T1.A, T1.B, T1.C, T2.J, T1.M, T1.N, T3.P</code></p>
  
  <p>Fortunately, rows' attributes coincide on homonymous columns, ie.</p>
  
  <p><code>T1.A == T2.A == T3.A</code> across all rows</p>
  
  <p><code>T1.B = T2.B</code> across all rows</p>
  
  <p>etc.</p>
  
  <p>What would be a query to join those tables into a single <code>R</code> table keeping only uniquely-named columns as above?</p>