client.query(selstring, function(err, result) {
       if(err){
         res.send(JSON.stringify(err));
         console.log(err);
       }else{

{ [error: column "undefined" does not exist]
  length: 98,
  name: 'error',
  severity: 'ERROR',
  code: '42703',
  detail: undefined,
  hint: undefined,
  position: '176',
  internalPosition: undefined,
  internalQuery: undefined,
  where: undefined,
  file: 'parse_expr.c',
  line: '766',
  routine: 'transformColumnRef' }