sql union命令

Question

我有一个名字和高度的学生表。我想要一个查询，按字母顺序排列150cm以上的学生，按照名字的降序排列小于150cm的学生。

这样的事情：

(select * from students where height >= 150 order by name)  
union 
(select * from students where height < 150 order by name desc)

它不起作用，因为联合搞乱了子查询中行的顺序。我知道这是正常的，联合输出一组，并且在一组中它的顺序并不重要。有什么像追加？

Answer 1

   SELECT *
   FROM students
   ORDER BY IF(height >= 150, 1,0 ) DESC, 
            IF(height >= 150, name, '') ASC, 
            name DESC

示例输出

+------+--------+
| name | height |
+------+--------+
| a    |    189 |
| m    |    666 |
| thy  |    166 |
| yyy  |   1277 |
| zz   |    101 |
| swq  |    122 |
| n    |    111 |
| g    |    145 |
+------+--------+

Answer 2

select *, case when height >= 150 then 1 else 0 end as tallstudent 
from students order by tallstudent, name