下面我建兩個表，並執行一系列sql語句，仔細觀察sql執行後表中資料的變化，很容易就能理解多表聯合更新的用法

student表                                                                         class表

1. 執行 UPDATE student s , class c SET s.class_name='test00',c.stu_name='test00' WHERE s.class_id = c.id

student表                                                                class表

2. 執行 UPDATE student s JOIN class c ON s.class_id = c.id SET s.class_name='test11',c.stu_name='test11'

student表                                                                  class表

3. 執行 UPDATE student s LEFT JOIN class c ON s.class_id = c.id SET s.class_name='test22',c.stu_name='test22'

student表                                                                      class表

4. 執行 UPDATE student s RIGHT JOIN class c ON s.class_id = c.id SET s.class_name='test33',c.stu_name='test33'

student表                                                                class表

5. 執行 UPDATE student s JOIN class c ON s.class_id = c.id SET s.class_name=c.name , c.stu_name=s.name

student表                                                                class表