SQL OUTER JOIN

不象SQL INNER JOIN，SQL OUTER JOIN外联接两个联接表，即使它们没有匹配。

有三种类型的外联接SQL OUTER JOIN：
SQL LEFT OUTER JOIN
SQL RIGHT OUTER JOIN
SQL FULL OUTER JOIN

SQL OUTER JOIN 范例

数据表： Employees

选择所有的职员(Employee)和Email地址：

SELECT  emp.EmployeeId, emp.FirstName, emp.LastName, Email.Email
FROM Employees AS emp
     LEFT OUTER JOIN Email
     ON emp.EmployeeId = Email.EmployeeId

结果会类似于：