ANSI / ISO SQL：2003引入了 窗口函数 ：
SELECt * FROM ( SELECt ROW_NUMBER() OVER (ORDER BY age ASC) AS rownum, person_id, person_name, age FROM person) AS fooWHERe rownum <= 3
自SQL Server 2005起，Microsoft SQL Server就支持此语法。http: //msdn.microsoft.com/zh-
cn/library/ms189798(v=sql.90).aspx
ANSI / ISO SQL：2008为引入了一种更简单的语法
FETCH FIRST，该语法可能更类似于Microsoft /
Sybase
TOP语法：
SELECt person_id, person_name, age FROM personFETCH FIRST 3 ROWS ONLY
Microsoft尚不支持此语法。另请参见http://en.wikipedia.org/wiki/Select_(SQL)#Limiting_result_rows
