高手求一SQL语句，高手请进！！！！！！！

Question

表二写错了，以下为更正后的内容
表二，客户联系人列表 customer_link
customer_link_id number(10)//客户联系人ID，索引，无重复
customer_link_name varchar2(100)//客户联系人名字
customer_id   number(10)      //表一中的ID

Answer 1

SELECT a.customer_id,b.customer_link_name FROM customer a,customer_link b
WHERE a.customer_link_id = b.customer_link_id(+)
ORDER BY a.customer_id

Answer 2

select a.customer_id,nvl(b.customer_link_name,'无') from
customer a,customer_link b where a.customer_link_id=b.customer_link_id(+);

Answer 3

select a.customer_id,nvl(b.customer_link_name,'empty') from
customer a,customer_link b where a.customer_link_id=b.customer_link_id(+);

Answer 4

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