来自多个表的SQL SELECT [英] SQL SELECT from multiple tables
本文介绍了来自多个表的SQL SELECT的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
如何从客户1和客户2的所有产品中获取他们的客户名称?
How can I get all products from customers1 and customers2 include their customer names?
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
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
推荐答案
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
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