表A(key,v1),表B(key,v2)，其中连接的公共字段key。假设A为左表，下面代码中能实现左反连接的是（ ）

A.select * from A left join B on A.key=B.key where v2 is null;
B.select * from A left join B using(key) where v2 is not null;
C.select * from A,B where A.key=B.key and v1 is null;
D.Select * from A left join B using(key) where v1 not in (select v1 from A inner join B using(key));

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