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
