Java如何打印a.rowname

Question

我问自己，我是如何用Java打印a.rowname的。还是我采取了错误的解决方案来获取所有选定的数据？

我试过这个：

String vergleichVon ="DB_18_12_2021_02h13m05s";
String vergleichBis ="DB_18_12_2021_08h28m19s";

Connection connection = null;
try
{
    //Connect to Database
    connection = DriverManager.getConnection("jdbc:sqlite:"+dataBasePath+"");
    Statement c = connection.createStatement();
    c.setQueryTimeout(30);  // set timeout to 30 sec.

    ResultSet rs = c.executeQuery("SELECT a.name, a.pt, b.pt, a.sz, a.bd"+
                                    "FROM "+vergleichVon+" AS a, "+vergleichBis+" AS b "+
                                    "WHERE a.name= b.name AND a.pt>'1000' AND b.pt>='1000' AND a.pt!='n/v' AND b.pt!='n/v' "+
                                    "ORDER BY a.pt DESC");
    while(rs.next())
    {
      // read the result set
      System.out.print("nameA = " + rs.getString("a.name"));
      System.out.print(" ");
      System.out.println("ptB = " + rs.getString("b.pt"));
    }
}

我得到了一个错误：

no such column: 'a.name' 

在Python中，它的工作方式是这样的。稍后，我可以从数组中获取选定的数据：

c.execute('''SELECT a.name, a.pt, b.pt, a.sz, a.bd
          FROM '''+vergleich_von+''' AS a, '''+vergleich_bis+''' AS b
          WHERE a.name= b.name AND a.pt>'1000' AND b.pt>='1000' AND a.pt!='n/v' AND b.pt!='n/v'
          ORDER BY a.pt DESC''')
array = c.fetchall()

Answer 1

您没有选择a.spieler

尝试：

ResultSet rs = c.executeQuery("SELECT a.name as spieler, a.pt, b.pt as bpt, a.sz, a.bd"+
                                "FROM "+vergleichVon+" AS a, "+vergleichBis+" AS b "+
                                "WHERE a.name= b.name AND a.pt>'1000' AND b.pt>='1000' AND a.pt!='n/v' AND b.pt!='n/v' "+
                                "ORDER BY a.pt DESC");
while(rs.next())
{
  // read the result set
  System.out.print("nameA = " + rs.getString("spieler"));
  System.out.print(" ");
  System.out.println("ptB = " + rs.getString("bpt"));
}

问题后的更新，编辑，对没有点的列使用别名：

ResultSet rs = c.executeQuery("SELECT a.name as name, a.pt as apt, b.pt as bpt, a.sz as asz, a.bd as adb"+
                                "FROM "+vergleichVon+" AS a, "+vergleichBis+" AS b "+
                                "WHERE a.name= b.name AND a.pt>'1000' AND b.pt>='1000' AND a.pt!='n/v' AND b.pt!='n/v' "+
                                "ORDER BY a.pt DESC");
while(rs.next())
{
  // read the result set
  System.out.print("nameA = " + rs.getString("name"));
  System.out.print(" ");
  System.out.println("ptB = " + rs.getString("bpt"));
}