Question

I’m using NetBeans IDE for connecting with MySQL database and I want to use select query that take input value from user and put that value in where condition .
and I get this error message
Unknown column ‘A’ in ‘where clause’
It works when I write the value ‘A’ in the code, but it doesn’t work when its an input from the user?

String dataSourceName = "testSqlDb";
String dbUrl = "jdbc:odbc:" + dataSourceName;
try {
  bloodgroup = jTextField2.getText().trim();
  Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
  Connection con = DriverManager.getConnection(dbUrl, "", "");
  Statement s = con.createStatement();

  ResultSet rs;
  String query = "SELECT COUNT(*) FROM blood_donation WHERE blood_group="
      + bloodgroup;

  rs = s.executeQuery(query);

  while (rs.next()) {
    System.out.println("COUNT(*)=" + rs.getInt("COUNT(*)"));
  }

  s.close();
  con.close();

} catch (Exception e) {
  System.out.println(e.getMessage());
  JOptionPane.showMessageDialog(null, e.getMessage(), "erro",
      JOptionPane.ERROR_MESSAGE, null);
}

Answer 1

I guess you are missing the ‘ ‘

String query = "SELECT COUNT(*) FROM blood_donation WHERE blood_group='"+bloodgroup+"'";