在MySQL中，想要對(duì)表的多次查詢結(jié)果分別排序合并是不可行的
如：

SELECT name FROM student
ORDER BY age
UNION
SELECT grade FROM student
ORDER BY age;

為了避開(kāi)語(yǔ)法的問(wèn)題，有了下面的解決辦法，使用子查詢

SELECT * from
(SELECT name FROM student
ORDER BY age) t1
UNION (all)
SELECT * from
(SELECT grade FROM student
ORDER BY age);

順利通過(guò)，可是查看結(jié)果會(huì)發(fā)現(xiàn)，排序失效了。因?yàn)樽硬樵円?guī)則是沒(méi)有top語(yǔ)句（mysql中用limit代替），
排序不生效，再次修改：

SELECT * from
(SELECT name FROM student
ORDER BY age limit 0, 1000) t1
UNION (all)
SELECT * from
(SELECT grade FROM student
ORDER BY age limit 0, 1000);

原文：https://blog.csdn.net/zhouli2008/article/details/79780117