SQL variable in jdbc

Question

I'd like to retrieve one result but I have to use @variable in sqls like below.
1) select @variable := b_id from cp_contents_test where contentid = "8593B9B13A2105B5E252FB11F1FF0822";
2) select cp_contents_test.b_id,cap_member.mem_name,cap_member.mem_email,ctg_no,
title,subtitle,summary,keyword,description,imagelink,lname_0,lname_1,lname_2
,lurl_0,lurl_1,lurl_2, fname,fsize,down,point,creationDate,ip,hit
from cp_contents_test,cap_member,links
where cp_contents_test.mem_no=cap_member.mem_no
and cp_contents_test.b_id = links.b_id
and cp_contents_test.b_id=@variable;
I just like to know how to use those two sql statements in jdbc...
Is there any specific way to use a variable in jdbc?

Answer 1

Is there any specific way to use a variable in jdbc?You can use a "?" as a placeholder for a bind variable. You can then use the setXXX methods in the PreparedStatement class to set the value. The same PreparedStatement can be reused by setting new parameter values and re-executing.
public void runTest(Connection con, long[] ids) {
     PreparedStatement pstmt          = null;
     ResultSet rs               = null;
     long value               = 0;
     // Your SQL Statement
     String sql = "select column1 from table1 where column2 = ?";
     try {
          // Prepare it once
          pstmt = con.prepareStatement(sql);
          // Loop through your criteria...
          int size = ids.length;
          for (int i = 0; i < size; i++) {
               // Set the parameter value to the current criteria
               pstmt.setLong(1, ids);
               // (Re-)Execute the Query
               rs = pstmt.executeQuery();
               // Loop through the returned ResultSet...
               while (rs.next()) {
                    // and get the values
                    value = rs.getLong(1);
                    // Do something with value...
     } catch (SQLException) {
          // Handle Exception
     } finally {
          try {
               rs.close();
          } catch (Exception e) {}
          try {
               pstmt.close();
          } catch (Exception e) {}
It appeared that you were trying to set a parameter as the result of one SQL statement for use in a 2nd SQL statement. You can take a result retrieved in Java in the manner above and feed it to a 2nd PreparedStatement created the same way. However, in the specific example you gave, it appears the 2 queries really could have just been one....The 2nd query could have had cp_contents_test.contentid = "...." in the where clause.