mysql多表查询之交叉连接

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语法，返回笛卡尔积

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案例代码运行输出结果如下：

-- 交叉连接
mysql> select * from stuinfo cross join stumarks;
-- 交叉连接有连接表达式与内连接是一样的
mysql> select * from stuinfo cross join stumarks on stuinfo.stuno=stumarks.stuno;
+--------+----------+--------+--------+---------+------------+---------+--------+-------------+---------+
| stuNo | stuName | stuSex | stuAge | stuSeat | stuAddress | examNo | stuNo | writtenExam | labExam |
+--------+----------+--------+--------+---------+------------+---------+--------+-------------+---------+
| s25303 | 李斯文 | 女 | 22 | 2 | 北京 | s271811 | s25303 | 80 | 58 |
| s25302 | 李文才 | 男 | 31 | 3 | 上海 | s271813 | s25302 | 50 | 90 |
| s25304 | 欧阳俊雄 | 男 | 28 | 4 | 天津 | s271815 | s25304 | 65 | 50 |
| s25301 | 张秋丽 | 男 | 18 | 1 | 北京 | s271816 | s25301 | 77 | 82 |
| s25318 | 争青小子 | 男 | 26 | 6 | 天津 | s271819 | s25318 | 56 | 48 |
+--------+----------+--------+--------+---------+------------+---------+--------+-------------+---------+
5 rows in set (0.00 sec)