Java 和 MySQL 查询日期

Question

我的 Java 代码是这样的：

public void FillCombo_Disp(){
    java.sql.Date fromDate = new java.sql.Date(jDateChooser_Date1.getDate().getTime());
    java.sql.Date toDate= new java.sql.Date(jDateChooser_Date2.getDate().getTime());
    String space = jComboBox_Space.getSelectedItem().toString();
    String [] space_split = space.split(" ");
    String id_space = space_split[0];
    String query = "SELECT ID FROM Rent WHERE ID_Space = '" + id_space + "' AND Date1 BETWEEN ? AND ? OR Dat2 BETWEEN ? AND ?";
    try {
        pst = conn.Connection().prepareStatement(query);
        pst.setDate(1, fromDate);
        pst.setDate(2, toDate);
        pst.setDate(3, fromDate);
        pst.setDate(4, toDate);

        ResultSet res = pst.executeQuery();
        int ID = 0;
        while(res.next()) {
            ID = res.getInt("ID");
        }

        if(ID!=0)
            jTextField_Disp.setText("Rented");
        else
            jTextField_Disp.setText("Free");
    } catch(Exception e) {
        JOptionPane.showMessageDialog(null, e);
    }
}

我的功能是控制用户输入的两个日期并将它们与数据库进行比较。如果日期在时间范围内，你应该把 id_rent 还给我。 但是我不明白为什么不能进入while循环：

while(res.next()) {
    ID = res.getInt("ID");
}

帮帮我！

Answer 1

您在查询中犯了拼写错误，因此它不返回任何行。当我认为它应该是“Date2”时，你输入了“Dat2”这个词。

当前：

String query = "SELECT ID FROM Rent WHERE ID_Space = '" + id_space + "' AND Date1 BETWEEN ? AND ? OR Dat2 BETWEEN ? AND ?";

新：

String query = "SELECT ID FROM Rent WHERE ID_Space = '" + id_space + "' AND Date1 BETWEEN ? AND ? OR Date2 BETWEEN ? AND ?";