在mysql中如果我們是聯(lián)合查詢經常會需要使用到as了,因為兩個表中如果有同名字段,不加一區(qū)別我們都無法確定是調用那個表中的數據.

① 表的SQL Alias 語法,代碼如下:

SELECT column_name(s) FROM table_name AS alias_name

例子,代碼如下:

SELECT po.OrderID, p.LastName, p.FirstNameFROM Persons AS p, Product_Orders AS poWHERE p.LastName='Adams' AND p.FirstName='John'  //Vevb.com

② 列的SQL Alias 語法,代碼如下:

SELECT column_name AS alias_name FROM table_name

例子,代碼如下:

SELECT LastName AS Family, FirstName AS Name FROM Persons