Question

我有2个以下的选择查询。我想将第一个选择查询结果的结果与第二个选择查询结果相除，并将此结果乘以100以计算百分比。但不知道该怎么做。

select count(*) from rate_errors where id > to_char(SYSTIMESTAMP - INTERVAL '1' HOUR,'YYYYMMDDHH24MISS')||'0000'

select count(*) from SDR_O2 where id > to_char(SYSTIMESTAMP - INTERVAL '1' HOUR,'YYYYMMDDHH24MISS')||'0000'

Answer 1

我倾向于用cross join：

来做这件事

select r.cnt / o.cnt
from (select count(*) as cnt
      from rate_errors
      where id > to_char(SYSTIMESTAMP - INTERVAL '1' HOUR, 'YYYYMMDDHH24MISS') ||'0000'
     ) r cross join
     (select count(*) as cnt
      from SDR_O2
      where id > to_char(SYSTIMESTAMP - INTERVAL '1' HOUR, 'YYYYMMDDHH24MISS')||'0000'
    ) o;

如果需要，可以将id计算分解为CTE：

with params as (
      select to_char(SYSTIMESTAMP - INTERVAL '1' HOUR, 'YYYYMMDDHH24MISS')||'0000'
      from dual
     )
select r.cnt / o.cnt
from (select count(*) as cnt
      from params cross join rate_errors re
      where re.id > params.id
     ) r cross join
     (select count(*) as cnt
      from params cross join SDR_O2 o
      where o.id > params.id
    ) o;

这样可以更轻松地更改id，并确保两个子查询的逻辑相同。

Answer 2

with x as 
(select count(*) rcnt from rate_errors where id > to_char(SYSTIMESTAMP - INTERVAL '1' HOUR,'YYYYMMDDHH24MISS')||'0000')
, y as (select count(*) scnt from SDR_O2 where id > to_char(SYSTIMESTAMP - INTERVAL '1' HOUR,'YYYYMMDDHH24MISS')||'0000')
select 100*rcnt/scnt from x, y;

您可以使用cte＆＃39>来完成此操作。但是，如果上面的x和y之间没有关系，则无法确定结果。

如何划分两个选择查询结果并计算百分比

2 个答案: