獲得前N個結果爲每列值

Question

我有這樣的一個表：

+--------+--------+ 
| name | kind | 
+--------+--------+ 
| cat | animal | 
| dog | animal | 
| horse | animal | 
| ant | animal | 
| bird | animal | 
| tree | plant | 
| grass | plant | 
| carrot | plant | 
|     | 
|  ... etc. | 
+--------+--------+ 

我怎樣才能得到每個樣的前N個項目？例如。 N = 2：

+--------+--------+ 
| name | kind | 
+--------+--------+ 
| ant | animal | 
| bird | animal | 
| carrot | plant | 
| grass | plant | 
+--------+--------+ 

在此先感謝！

Answer 1

這裏是一個SqlFiddle demo：

select name,kind from 
(

select Name,Kind, 
     @i:=if(@kind=kind,@i+1,1) rn, 
     @kind:=kind 
     from t, (select @i:=0,@kind:='') d 
     order by Kind,name 
) t1 
where t1.rn<=2 
    order by Kind,name 

的[在MySQL ROW_NUMBER（）]