按数字顺序，然后是字母，然后是空值

Question

我的数据库中有以下列：

abc
1
2
null
100
6

我想按照以下顺序对这些值进行排序和显示：

1
2
6
100
abc
null

任何人请帮我解决它。考虑以下查询：

select * from test_table where status=1 order by test_column DESC

或者

 select * from test_table where status=1 order by if((test_column = '' OR test_column IS NULL),'999999',test_column) DESC

Answer 1

select
*
from
t
order by
case 
when col regexp '^[0-9]' then 1
when col regexp '^[a-zA-Z]' then 2
when col = '' or col is null then 3
end
, col * 1 /*this converts to number, so that 100 is not sorted before 2*/
, col /*finally sort strings correctly*/