SQL Alias 别名

SQL 别名(Alias)是用于组织输出,使得它更易读和更有含义。SQL别名(Alias)可以用于表名,也可以用于列名。

SQL 别名(Alias) 语法

SELECT T.Column1 AS c1, T.Column2 AS c2, T.Column3 AS c3, ...
FROM TABLE1
AS T

SQL 别名(Alias) 范例

数据表: Employees

EmployeeId FirstName LastName Department Salary
203 Marfg Fxun Finance 78000
204 Joznk Llnyo Finance 45800
205 Hasuu Kynuoo Finance 57000
206 Jkucc Qihha Finance 62000
302 Biee Uioooi Development 75000
303 Kmoao Astuu Development 55000
304 Pissue Koooi Development 49000

选择所有职员(Employee)的人数:

SELECT COUNT(E.EmployeeId) AS totalEmployees
FROM Employees AS E

结果会类似于:

totalEmployees
7