两个表连接：inner join要两个都有，right outer join是要右边的表有这个数据（on后面的），left outer join是要左边的有这个数据，full outer join只要某一张有就可以
leetcode 175
无难度，连接俩表，要左边数据的都要 用left outer join
select FirstName,LastName,City,State From Person left outer join Address on Person.PersonId=Address.PersonId
原文：https://www.cnblogs.com/tingxilin/p/13174411.html
