标签：
Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | PersonId | int | | FirstName | varchar | | LastName | varchar | +-------------+---------+ PersonId is the primary key column for this table. Table: Address +-------------+---------+ | Column Name | Type | +-------------+---------+ | AddressId | int | | PersonId | int | | City | varchar | | State | varchar | +-------------+---------+ AddressId is the primary key column for this table. Write a SQL query for a report that provides the following information for each person in the Person table, regardless if there is an address for each of those people: FirstName, LastName, City, State
Select Person.FirstName,Person.LastName,Address.City,Address.State from Person LEFT OUTER JOIN Address on Person.PersonId = Address.PersonId
连接类型 定义内连接 只连接匹配的行左外连接 包含左边表的全部行（不管右边的表中是否存在与它们匹配的行），以及右边表中全部匹配的行右外连接 包含右边表的全部行（不管左边的表中是否存在与它们匹配的行），以及左边表中全部匹配的行全外连接 包含左、右两个表的全部行，不管另外一边的表中是否存在与它们匹配的行。(H)(theta)连接 使用等值以外的条件来匹配左、右两个表中的行交叉连接 生成笛卡尔积－它不使用任何匹配或者选取条件，而是直接将一个数据源中的每个行与另一个数据源的每个行都一一匹配
标签：
原文地址：http://www.cnblogs.com/hixin/p/4797989.html
