查询一个表里的每条记录在另一个表里是否存在，在返回1，不在返回0

sql语句： select decode(b.cid, null, 0, 1)   from CUSTOMER  a left join (select cid from customer_staff)b on a.cus_id=b.cid and a.cus_id=5380;

如果想返回id，将decode(b.cid, null, 0, 1)换为nvl(b.id,0)