Question

我在java应用程序的下拉列表中有所有表名。我想在JLabel上显示表中的记录数。但我收到以下错误

java.sql.SQLSyntaxErrorException：ORA-00903：表名无效

我试过这个：

try {
        String tableName = LoginFrame.userName + "." +    this.ddlTableName.getSelectedItem().toString();
        JOptionPane.showMessageDialog(null, tableName);
        pst = (OraclePreparedStatement) con.prepareStatement("select count(*) as num from '" + tableName + "'");
        rs = pst.executeQuery();
        while (rs.next()) {
            this.lblRecordStat.setText(rs.getString("num"));
        }
    } catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, ex);
        System.out.println(ex);
    }

Answer 1

在Oracle中，引号（' s）用于表示字符串文字。对象名称（例如表）不应该被它们包围。丢失报价，你应该没问题：

pst = (OraclePreparedStatement) con.prepareStatement
          ("select count(*) as num from " + tableName);

Answer 2

您正在将字符串作为表名传递。 Oracle中的表名可以在``qoutes里面，也可以没有任何引号。

pst = (OraclePreparedStatement) con.prepareStatement("select count(*) as num from " + tableName );

或

pst = (OraclePreparedStatement) con.prepareStatement("select count(*) as num from `" + tableName + "`");

java.sql.SQLSyntaxErrorException：ORA-00903：表名无效

2 个答案: