ການສະແດງວິດີໂອ SQL Alias (ປະຕິກິດ)

通过使用 SQL，可以为列名称和表名称指定别名（Alias）。

SQL Alias

表的 SQL Alias 语法

SELECT column_name(s)
FROM table_name
AS alias_name

列的 SQL Alias 语法

SELECT column_name AS alias_name
FROM table_name

Alias 实例: 使用表名称别名

Assuming we have two tables named "Persons" and "Product_Orders". We assign aliases "p" and "po" to them.

Now, we want to list all orders for "John Adams".

We can use the following SELECT statement:

SELECT po.OrderID, p.LastName, p.FirstName
FROM Persons AS p, Product_Orders AS po
WHERE p.LastName='Adams' AND p.FirstName='John'

SELECT statement without alias:

SELECT Product_Orders.OrderID, Persons.LastName, Persons.FirstName
FROM Persons, Product_Orders
WHERE Persons.LastName='Adams' AND Persons.FirstName='John'

From the two SELECT statements above, you can see that aliases make the query program easier to read and write.

Alias example: Using a column alias

Table Persons:

Id LastName FirstName Address City
1 Adams John Oxford Street London
2 Bush George Fifth Avenue New York
3 Carter Thomas Changan Street Beijing

SQL:

SELECT LastName AS Family, FirstName AS Name
FROM Persons

ຜົນຄະແນນ:

Family Name
Adams John
Bush George
Carter Thomas