Question

如何在Java查询中使用组合框的值？我尝试使用此代码，但它不起作用。

String sql = " select * from table1 where ? like ?";
    try{
        pst = conn.prepareStatement(sql);
        pst.setString(1, (String) jComboBox2.getSelectedItem());
        pst.setString(2, txtsearch.getText() + "%");
        rs = pst.executeQuery();}

如果我使用此代码，它可以工作。

String sql = " select * from table1 where Name like ?";
    try{
        pst = conn.prepareStatement(sql);
        pst.setString(1, txtsearch.getText() + "%");
        rs = pst.executeQuery();}

Answer 1

嗯，你可以这样做：

try {
    String sql = "select * from table1 where ";
    sql += (String) jComboBox2.getSelectedItem();
    sql += " like ";
    sql += txtsearch.getText() + "%";
    pst = conn.prepareStatement(sql);
    rs = pst.executeQuery();
}

Answer 2

占位符（？）实际上是为列值而不是列/表名设计的。使用字符串连接：

String sql = "select * from table1 where "
                                  + jComboBox2.getSelectedItem()
                                  +" like ?";

在SQL查询中使用组合框的值

2 个答案: