通过使用 SQL,别名(Alias)可用于列名称和表名称。
列名别名
语法:
SELECT 列名称 AS 列的别名 FROM 表名称;
表名称别名
语法:
SELECT 列名称 FROM 表名称 AS 表的别名;
实例 1: 使用一个列名别名
表(Persons):
| LastName | FirstName | Address | City |
|---|
| Hansen | Ola | Timoteivn 10 | Sandnes |
| Svendson | Tove | Borgvn 23 | Sandnes |
| Pettersen | Kari | Storgt 20 | Stavanger |
SQL:
SELECT LastName AS Family, FirstName AS Name FROM Persons;
结果:
| Family | Name |
|---|
| Hansen | Ola |
| Svendson | Tove |
| Pettersen | Kari |
实例: 使用一个表名称别名
表(Persons):
| LastName | FirstName | Address | City |
|---|
| Hansen | Ola | Timoteivn 10 | Sandnes |
| Svendson | Tove | Borgvn 23 | Sandnes |
| Pettersen | Kari | Storgt 20 | Stavanger |
SQL:
SELECT LastName, FirstName FROM Persons AS Employees;
结果:
表 Employees:
| LastName | FirstName |
|---|
| Hansen | Ola |
| Svendson | Tove |
| Pettersen | Kari |