Joining two relations with default values <p>I have two views:</p> <pre><code>view1 view2 obj obj attribute +-+ +-+--+ |A| |C|27| +-+ +-+--+ |B| +-+ |C| +-+ </code></pre> <p>How can I combine the values and return the output,</p> <pre><code>obj attribute +-+--+ |A| 0| +-+--+ |B| 0| +-+--+ |C|27| +-+--+ </code></pre> <p>with 0's as default values in SQL? I don't want to use PL/SQL.</p>