title: Joining two tables when there is a not matching record exist
body: <p>I am trying to use 1 sql statement to produce the result I want.
  I got 2 tables named , order and customers,  and tried to use a query like this</p>
  
  <pre><code>select a.*, b.customers_name 
  from order a, customers b 
  where a.customers_id=b.customers_id   
  order by b.customers_name;
  </code></pre>
  
  <p>My problem is there is a fake customers_id in order table, if customers_id=0 then
  customers_name='In House' which does not exist in cumstomers table. 
  It's been used like this way before I joined this company so I can not modify the table at all.</p>
  
  <p>Is there way to display the result?
  All order from order table with customers_name and if customers_id=0 (&lt;= no match record in customers table) then customers_name='In House') and output should be ordered by customers_name.</p>