使用mysql从不同表行合并两列

假设每个表中的列数相同,则可以按行号链接它们。没有一个 ORDER BY 子句,但行编号是不确定的,不能保证结果。

在MySQL 5.7及以下版本中:

SELECT Name, Grade, Type, Class
FROM (SELECT *, @rownum := @rownum + 1 AS rownum
      FROM Student
      CROSS JOIN (SELECT @rownum := 0) r
      ) s
JOIN (SELECT *, @rownum2 := @rownum2 + 1 AS rownum
      FROM Type
      CROSS JOIN (SELECT @rownum2 := 0) r
      ) t ON t.rownum = s.rownum

在MySQL8.0及以上版本中:

SELECT Name, Grade, Type, Class
FROM (SELECT *, ROW_NUMBER() OVER () AS rownum
      FROM Student) s
JOIN (SELECT *, ROW_NUMBER() OVER () rownum
      FROM Type) t ON t.rownum = s.rownum

输出:

Name    Grade   Type    Class
John    A+      Good    12
Tina    B       Avg     11

Demo on dbfiddle