java 取结果集的最后三项，

Question

数据库是oracle 10G

我现在插入数据：

insert into you (id,name) values (1,'john1');

insert into you (id,name) values (2,'john2');

insert into you (id,name) values (3,'john3');

insert into you (id,name) values (4,'john4');

insert into you (id,name) values (5,'john5');

我想取最后三条记录，

3 john3

4 john4

5 john5

这个怎么实现呢？ 请指教

Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
conn = DriverManager.getConnection(
"jdbc:oracle:thin:@localhost:1521:orcl", "zhang",
"zhang");
stmt = conn.createStatement();
String url = "select * from you where rownum<=3 order by id desc";

我这里只能取到前三条，取不了后三条，
rs = stmt.executeQuery(url);
while (rs.next()) {
out.print(rs.getString("id"));
out.print(rs.getString("name"));
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (rs != null) {
rs.close();
}
if (stmt != null) {
stmt.close();
}
if (conn != null) {
conn.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}

Answer 1

SELECT * FROM (SELECT * FROM you ORDER BY id DESC ) WHERE ROWNUM<=3;

如果ID是自增的，这样应该是可以的。