WITH t AS 
(
SELECT 'A' switch_code, 'u' status FROM dual
UNION ALL
SELECT 'A' , 'r' status FROM dual
UNION ALL
SELECT 'A' , 'd' status FROM dual
UNION ALL
SELECT 'A' , 'a' status FROM dual
UNION ALL
SELECT 'A' , 'd' status FROM dual
UNION ALL
SELECT 'A' , 'u' status FROM dual
UNION ALL
SELECT 'A' , 'u' status FROM dual
UNION ALL
SELECT 'A' , 'u' status FROM dual
)

SELECT switch_code,
       SUM(decode(status,'u',1,0))/COUNT(switch_code) u占有率,
       SUM(decode(status,'a',1,0))/COUNT(switch_code) a占有率,
       SUM(decode(status,'d',1,0))/COUNT(switch_code) d占有率,
       SUM(decode(status,'r',1,0))/COUNT(switch_code) r占有率
       FROM t
       GROUP BY switch_code

--result:
A    0.5    0.125    0.25    0.125

------解决方案--------------------

SQL code
select sum(decode(status,'U',1,0))/count(1)*100
from switch_port c 
group by switch_code