SQL SELECT从多个表

如何从客户1获得所有产品,客户2包括客户名称？

customer1 table
cid name1
1   john
2   joe

customer2 table
cid name2
p1  sandy
p2  linda

product table
pid cid pname
1   1   phone
2   2   pencil
3   p1  pen
4   p2  paper

结果应该是这样的

pid  cid  pname  name1 name2
1    1    phone  john  NULL
2    2    pencil joe   NULL
3    p1   pen    NULL  sandy
4    p2   paper  NULL  linda

解决方法

SELECT p.pid,p.cid,p.pname,c1.name1,c2.name2
FROM product p
LEFT JOIN customer1 c1 ON p.cid = c1.cid
LEFT JOIN customer2 c2 ON p.cid = c2.cid