id是指当前数据news_id参数

    方法一：

    string preSql = "select top 1 * from news where news_id < " + id + " order by news_id DESC"

    string nextSql = "select top 1 * from news where news_id > " + id + " order by news_id ASC"

    方法二：

    string preSql = "select * from [news] where news_id = (select MAX(news_id) from [news] where news_id<"+ id + ")";

    string nextSql = "select * from [news] where news_id = (select MIN(news_id) from [news] where news_id>"+ id + ")";