計算條件 >=15 的道路百分比（按長度）

我有一張路況表：

CONDITION       LENGTH
   2              5
   4             10
   6             15
   8             20
  10             25
  12             30
  14             35
  16             40
  18             45
  20             50

狀況為15 或更高（又名）的道路15_OG被認為狀況良好。

我想計算狀況良好的道路百分比（按長度） 。

LENGTH_15_OG    TOTAL_LENGTH    PERCENT_15_OG
    135             275            49.09%

---

我該怎麼做這個計算？

只需稍作修改即可保存 1 個表訪問：

select
 length_15_og, total_length,
 round(length_15_og/total_length*100, 2) as percent_15_og
from
(
 select
   sum(case when condition >= 15 then length end) as length_15_og,
   sum(length) as total_length
 from
   road_condition
);

會有其他解決方案 - 但如何……

select 
 length_15_og
, total_length
, round( length_15_og / total_length * 100, 2 ) as percent_15_og
from (
 select 
   ( select sum( length ) from road_condition where condition >= 15 ) as length_15_og
 , ( select sum( length ) from road_condition ) as total_length
 from dual
) ;

-- result
LENGTH_15_OG  TOTAL_LENGTH  PERCENT_15_OG  
135           275           49.09 

小提琴

引用自：https://dba.stackexchange.com/questions/208920