title: SQL SELECT from multiple tables
body: <p>How can I get all products from customers1 and customers2 include their customer names?</p>
  
  <pre><code>customer1 table
  cid name1
  1   john
  2   joe
  
  customer2 table
  cid name2
  p1  sandy
  p2  linda
  
  product table
  pid cid pname
  1   1   phone
  2   2   pencil
  3   p1  pen
  4   p2  paper
  </code></pre>
  
  <p>Result should be like this</p>
  
  <pre><code>pid  cid  pname  name1 name2
  1    1    phone  john  NULL
  2    2    pencil joe   NULL
  3    p1   pen    NULL  sandy
  4    p2   paper  NULL  linda
  </code></pre>