title: JDBC SQL query has no result when it has result in SQL application
body: <p>When I write the following query in SQL application, it works fine, get the result as I expected.</p>
  
  <pre><code>SELECT
  stu_fname,
  stu_lname,
  sb_classname,
  sb_classdate,
  sb_stime
  FROM
  atp_sign_book,
  atp_student 
  WHERE
  sb_classdate &gt;= CURRENT_TIMESTAMP 
  AND sb_operation = 'Booking'
  AND atp_sign_book.stu_id = atp_student.stu_id
  ORDER BY
  sb_classdate,sb_stime
  </code></pre>
  
  <p>but when I try to use Java code to get same result, it has no result</p>
  
  <pre><code>ResultSet rSet = statement.executeQuery("SELECT stu_fname,stu_lname,sb_classname,sb_classdate,sb_stime"+
                  "FROM atp_sign_book, atp_student" + 
                  "WHERE sb_classdate &gt;= CURRENT_TIMESTAMP AND sb_operation = 'Booking' AND atp_sign_book.stu_id = atp_student.stu_id ORDER BY sb_classdate, sb_stime");
  </code></pre>
  
  <p>and I tried to remove part of the code to see how it works, and I found that as long as I add </p>
  
  <pre><code>atp_sign_book.stu_id = atp_student.stu_id
  </code></pre>
  
  <p>the result becomes nothing</p>