摘要：
测试表A 测试表B 1 left join(left outer join)--左连接包含左侧表中的所有数据 及按where条件查出的右表中的数据。不存在则显示空值select * from A left join B on a.name=b.name2 right join(right outer join)select * from A right join B on a.name=b.name--右连接与左连接恰好相反3 full join (full outer join)select*fromAfulljoinBona.name=b.name左连接和右连接的合集4 inner joi 阅读全文
