SQLServer 4类join查询:inner join,left join, right join, full outer join
1.from A inner join B on A.ID=B.ID :两表都有的记录才列出 A表: ID Name B表: ID Cla ...
1.from A inner join B on A.ID=B.ID :两表都有的记录才列出 A表: ID Name B表: ID Cla ...