How to count data in Java MySQL

Question

How to count data in Java and MySQL? The final result is shown to me through JOptionpane but I got an error message with this code.

 try { DBConn.conn = DriverManager.getConnection(DBConn.Url, DBConn.User, DBConn.PWD);
          java.sql.Statement count = DBConn.conn.createStatement();
          String SQLCount = "select count(*) from datastudent where parklevel = 'Level 1' ";
                ResultSet rs = count.executeQuery(SQLCount);
                  while (rs.next()) {
                    JOptionPane.showMessageDialog(null,"number of existing parking is " + rs);
                }
            } catch (Exception e2) {
            //
            }
       }

What is the error message?

rgettman
– rgettman

2013-11-25 18:03:29 +00:00
Commented Nov 25, 2013 at 18:03 — rgettman
– rgettman, Commented Nov 25, 2013 at 18:03
stackoverflow.com/questions/3988788/…

isnot2bad
– isnot2bad

2013-11-25 18:08:07 +00:00
Commented Nov 25, 2013 at 18:08 — isnot2bad
– isnot2bad, Commented Nov 25, 2013 at 18:08

Eran · Accepted Answer · 2013-11-25 18:03:59Z

1

You should print rs.getInt (1). When you select a count of some data from some table, the result is returned as an integer column in the result set.

So try :

JOptionPane.showMessageDialog(null,"number of existing parking is " + rs.getInt (1));

answered Nov 25, 2013 at 18:03

Eran

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subash · Accepted Answer · 2013-11-25 18:09:20Z

0

try this. your query return only one value, so no need loop.

           ResultSet rs = count.executeQuery(SQLCount);
           rs.next();
           JOptionPane.showMessageDialog(null,"number of existing parking is " + rs.getInt(1));

answered Nov 25, 2013 at 18:09

subash

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Comments

Konstantin · Accepted Answer · 2013-11-25 18:10:01Z

0

You're not reading any values from ResultSet, see javadocs. Needs rs.getInt(1)

answered Nov 25, 2013 at 18:10

Konstantin

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