title: Postgresql not supporting timestamp value on query
body: <pre><code>DECLARE
  MAX_upd_date_Entity_Incident timestamp without time zone;
  MAX_upd_date_Entity_Incident := (SELECT LAST_UPDATE_DATE::timestamp FROM 
  test.table_1 where TABLE_NAME='mac_incidents_d');
  
  execute 'insert into test.table2 (column_name,schema_name,tablename) 
  values(''col1'',''col2'',''col3'') from test.table3 X where X.dl_upd_ts::timestamp &gt; '||
  MAX_upd_date_Entity_Incident;
  </code></pre>
  
  <p>The above query is not getting executed, getting an error on the timestamp value, it's unable to read the variable <code>MAX_upd_date_Entity_Incident</code>. </p>
  
  <p>Please suggest me if we need to cast timestamp to another format.</p>
  
  <p>I am able to execute query in the SQL editor, but not using <code>execute</code>.</p>