SQL Select Top

数据表： Employees

EmployeeId	FirstName	LastName	Department	Salary
203	Mary	Fox	Finance	78000
204	Joe	Lanyon	Finance	45800
205	Sally	Daff	Finance	57000
206	Grace	Salter	Finance	62000
302	James	Band	Development	75000
303	Dona	Earl	Development	55000
304	Tony	Oakes	Development	49000
…

SQL Server

选择前10行数据：

SELECT TOP 10 *
FROM Employees

选择最高工资的前5个数据：

SELECT TOP 5 *
FROM Employees
ORDER BY Salary DESC

选择最高工资的前5%的数据：

SELECT TOP 5 PERCENT *
FROM Employees
ORDER BY Salary DESC

MySQL

选择最高工资的前10行数据：

SELECT *
FROM Employees
ORDER BY Salary DESC
LIMIT 10

Oracle

选择第一行记录：

SELECT *
FROM Employees
WHERE ROWNUM <= 1

选择最高工资的前100行记录：

SELECT *
FROM
  (
     SELECT *
     FROM Employees
     ORDER BY Salary DESC
  )
WHERE ROWNUM <= 100