title: Postgres: COALESCE all columns
body: <p>I'm dealing with a table that has way too many columns for good design. (Close to 100).  I can't change the schema.</p>
  
  <p>I need to COALESCE each column to be 0 on NULL.  Is there a way to do this without typing out all 100 columns by hand?  (Perhaps using some type of data dictionary or meta information?)</p>