MySQL : 我怎么加入这个table？

Question

我有这样的table，我想像输出table一样输出结果，谁能告诉我怎么做，在MySQL

Answer 1

早上好，您可以使用 LEFT JOIN

试一试：

SELECT tb_session.SESSION, tb_schedul.ID_CLASS FROM tb_session LEFT JOIN tb_schedul
ON tb_session.ID = tb_schedul.ID_SESSION;

Answer 2

您可以像这样使用左连接:

SELECT tb_session.SESSION AS SESSION, tb_class.CLASS AS CLASS from tb_schedul LEFT JOIN tb_session ON tb_schedule.ID_SESSION = tb_session.ID LEFT JOIN tb_schedul.ID_CLASS = tb_class.ID

MySQL : 我怎么加入这个table？

MySQL : How to I, join this table?

mysql

sql

join