在mysql数据库中按嵌套条件选择多行

在mysql数据库中按嵌套条件和嵌套限制选择多行

实际上我有一张桌子，像：

id  name   levels 
1   Red          1
2   Red Light    1
3   Green        2
4   Green Light  2
5   Blue         3
6   Blue Light   3
7   Blue Dark    3

I want fetch any rows according to levels with any limits Like: 
From Level-1 = 1 row
From Level-2 = 2 row
From Level-3 = 2 row
 total rows are 5 according to levels.
Any one know about single query is possible?
 or
three foreach loop will be implement? 

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任何人都能解决这个问题？任何人都能解决这个问题？