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P粉4733635272023-08-25 11:18:02
SELECT pid, cid, pname, name1, name2 FROM customer1 c1, product p WHERE p.cid=c1.cid UNION SELECT pid, cid, pname, name1, name2 FROM customer2 c2, product p WHERE p.cid=c2.cid;
P粉8264299072023-08-25 09:01:05
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