title: Concatenate in PostgreSQL
body: <p>I have a table with width and height (both integers). I want to display it as are.
  For eg: width = 300 and height = 160.
  Area = 300 x 160.
  I am using the following query </p>
  
  <pre><code>  select cast(concat(width,'x',height) as varchar(20)) from table;
  </code></pre>
  
  <p>or </p>
  
  <pre><code>select concat(width,'x',height) from table;
  </code></pre>
  
  <p>but I am getting the following error.</p>
  
  <pre><code>ERROR: function concat(character varying, "unknown", character varying) does not exist
  
  Hint: No function matches the given name and argument types. You may need to add explicit type casts.
  </code></pre>
  
  <p>Can anyone tell me how to do this?
  Thanks</p>