Duplicates in right outer join

Question

Please help me on fixing the query below,

select id, descr from table1 a
right join table2 b
on a.id = b.id

the descr has been populating null and duplicates. How to get rid of this duplicates in future?

Answer 1

使用不同的键，它将获取唯一的唯一键，如果您使用右连接和左连接，如果内容不存在，它将为空，因此仅使用连接。