以下为MySQL语句演示：
SELECT * FROM t_news AS n ORDER BY n.`News_ID`
当前ID为4，读取上一条记录：
SELECT * FROM t_news AS n WHERE n.`News_ID` < 4 ORDER BY n.`News_ID` DESC LIMIT 0,1;
当前ID为4，读取下一条记录：
SELECT * FROM t_news AS n WHERE n.`News_ID` > 4 ORDER BY n.`News_ID` LIMIT 0,1;
其他数据库，不用limit，改用top关键字即可。