title: function to_char(unknown, unknown) is not unique
body: <p>When running the following the query.<code>select * from surgicals where to_char(dt_surgery ,'DD-MM-YYYY' ) = to_char('12-02-2012','DD-MM-YYYY');</code></p>
  
  <p>the error coming as 'SQL state 42725: ERROR: function to_char(unknown, unknown) is not unique'</p>
  
  <p>How to run above select query?</p>