SQL Server 的语法：
SELECT TOP number|percent column_name(s)FROM table_name
等价

MySQL 语法
SELECT column_name(s) FROM table_nameLIMIT number
例子SELECT * FROM Persons LIMIT 5
Oracle 语法
SELECT column_name(s)FROM table_nameWHERE ROWNUM <= number
例子: SELECT * FROM Persons WHERE ROWNUM <= 5


select top 1 * from table
select top (1+2) * from table/*取前3行数据*/
区别就是()里面 是个表达式