code: func Random(db XODB) (float64, error) {
  	var err error
  
  	// sql query
  	const sqlstr = `SELECT pg_catalog.random()`
  
  	// run query
  	var ret float64
  	XOLog(sqlstr)
  	err = db.QueryRow(sqlstr).Scan(&ret)
  	if err != nil {
  		return 0.0, err
  	}
  
  	return ret, nil
  }
docs: // Random calls the stored procedure 'pg_catalog.random() double precision' on db.