title: cannot copy CSV into postgreSQL table : timestamp column won't accept the empty string
body: <p>I want to import a CSV file into version 9.2 but the CSV file has double-quote double-quote in the final column position to represent a NULL value:</p>
  
  <p><code>"2","1001","9","2","0","0","130","","2012-10-22 09:33:07.073000000",""</code></p>
  
  <p>which is mapped to a column of type Timestamp. postgreSQL doesn't like the "".  I've tried to set the NULL option but maybe I'm not doing it correctly? I've tried <code>NULL as '""</code> and <code>NULL ''</code> and <code>NULL as ''</code> and <code>NULL ""</code> but without success; here's my command:</p>
  
  <pre><code>COPY SCH.DEPTS 
  FROM 'H:/backups/DEPTS.csv' 
  WITH (
   FORMAT CSV,
   DELIMITER ',' ,
   NULL  '',
   HEADER TRUE,
   QUOTE   '"' 
   )
  </code></pre>
  
  <p>but it fails with an error:      </p>
  
  <blockquote>
    <p>ERROR:  invalid input syntax for type timestamp: ""</p>
    
    <p>CONTEXT:  COPY depts, line 2, column expirydate: ""</p>
  </blockquote>
  
  <p>P.S. Is there a way to specify the string representation of Booleans to the COPY command? The utility that produced the CSVs (of which there are many) used "false" and "true".</p>