Hello,
On Mon, 2019-09-02 at 06:28 +0000, Karen Goh wrote:
> Hi experts,
>
> I have been trying to find a solution in the internet but there is
> only 1 solution offered by stackoverflow in which the user uses if it
> is not there then use a else to print out there is no more data/row
> that appeared in that column.
>
> Basically, I was trying to get a List<String> which meet certain
> search condition so the data will come from 2 tables - one of which
> is a column from a join table and the List<String> falls under this
> table.
>
> So, here's the code that I attempt to get the data out but keep
> getting ResultSet not positioned properly.
>
> String[] subjectNames =
> request.getParameterValues("txtsubjects");
> String zipcode =
> request.getParameter("location");
> List<String> subjList = new
> ArrayList<String>(Arrays.asList(subjectNames));
> List<tutor> myList = new ArrayList<>();
> ArrayList<String> subList = new ArrayList<>();
> CopyOnWriteArrayList<String>newSub = new
> CopyOnWriteArrayList<String>();
> tutor t = new tutor();
>
>
> String sql1 = "select t.tutor_contact_no,
> t.zipcode, t.tutor_id, t2.subject_name FROM s_tutor t
> JOIN tutor_subject t2 ON t.tutor_id = t2.tutor_id where t.zipcode =
> ? And t2.subject_name = Any((?))";
>
> PreparedStatement ps2 =
> connection.prepareStatement(sql1);
> ps2.setString(1, zipcode);
> for (int i = 0; i < subjectNames.length; i++) {
> Array array =
> connection.createArrayOf("text", subjList.toArray());
> ps2.setArray(2, array);
> }
> ResultSet rs = ps2.executeQuery();
> while (rs.next()) {
> t.setContactNo(rs.getString("tutor_cont
> act_no"));
> t.setZipcode(rs.getString("zipcode"));
> t.settutor_id(rs.getInt("tutor_id"));
>
>
>
> for (String s: subjList)
> if
> (s.contains(rs.getString("subject_name")))
> subjList.add(rs.getString("subject_na
> me"));
> newSub.addAll(subjList);
> }
> myList.add(t);
> request.setAttribute("tutors", myList);
>
> request.setAttribute("sub", newSub);
>
> Please. I hope someone can tell me what's wrong with the code or how
> to overcome this error...I have been struggling for 2 weeks already.
>
> Thanks.
> }
> myList.add(t);
>
> request.setAttribute("tutors", myList);
>
> request.setAttribute("sub", newSub);
>
>
>
I'm not an "expert".
It is customary on these lists to supply the Postgres version, O/S,
JDBC driver version and the JDK version.
Also the error message from the PostgreSql log file.
Is t.zipcode defined as INTEGER or VARCHAR?
I would have used:-
AND T2.subject_name = ANY(string_to_array(?))
supplying a suitably constructed string as the second parameter.
You also need to cater for the query returning no rows.
HTH,
Robert
