字段ATTRIBUTE，按照3300-3305，3305-3310，3310-3315，3315-3320 进行分组，并求其频数，不在组中的频数为0，这种怎么写SQL，用case when 判断 最后求频率的时候不在区间内的数据，该区间就没有了，怎么能让区间还在频数为0。

select TO_NUMBER(x) as x,fz,count(fz) from (

select case when ATTRIBUTE2<'3295' then '<3295'

when ATTRIBUTE2>='3295' and ATTRIBUTE2<'3296' then '3295-3296'

 when ATTRIBUTE2>='3296' and ATTRIBUTE2<'3297' then '3296-3297'

 when ATTRIBUTE2>='3297' and ATTRIBUTE2<'3298' then '3297-3298'

 when ATTRIBUTE2>='3298' and ATTRIBUTE2<'3299' then '3298-3299'

 when ATTRIBUTE2>='3299' and ATTRIBUTE2<'3300' then '3299-3300'

 when ATTRIBUTE2>='3300'  then '>=3300'

 end as fz,

 case when ATTRIBUTE2<'3295' then '3294.5'

when ATTRIBUTE2>='3295' and ATTRIBUTE2<'3296' then '3295.5'

 when ATTRIBUTE2>='3296' and ATTRIBUTE2<'3297' then '3296.5'

 when ATTRIBUTE2>='3297' and ATTRIBUTE2<'3298' then '3297.5'

 when ATTRIBUTE2>='3298' and ATTRIBUTE2<'3299' then '3298.5'

 when ATTRIBUTE2>='3299' and ATTRIBUTE2<'3300' then '3299.5'

 when ATTRIBUTE2>='3300'  then '>=3300.5'

 end as x

 from 

(

SELECT 

equip_id,ATTRIBUTE2

FROM MT_DATA_RECORD_YZ_OCV1

WHERE 

equip_id='2680.1'

AND WORKCELL_ID ='58984.1'

AND TO_CHAR(record_date,'YYYYMMDDHH24')<= TO_CHAR(SYSdate,'YYYYMMDD')||'20'

AND TO_CHAR(record_date,'YYYYMMDDHH24')>= TO_CHAR(TO_CHAR(SYSdate,'YYYYMMDD')-1) ||'20'

ORDER BY tag_record_date desc )) group by fz,x

order by x