我可以考虑同时在left joins和2上进行product1。

select to_char(to_date(Date_Raised,'d-mon-yyyy'),'mon-yyyy'),(p2.product1 - sum(case when category_id='Product#1' then Defect_Quantity else 0 end))/p2.product1 * 100,(p2.product2 - sum(case when category_id='Product#2' then Defect_Quantity else 0 end))/p2.product2 * 100  
from tableA t1
left join 
    (select to_char(to_date(Date_Raised,'mon-yyyy') Date_Raised,sum(Comsumed_Quantity) as product1 tableB  
        where category_id = 'Product#1'
        group by to_char(to_date(Date_Raised,'mon-yyyy')) p1
    on p1.Date_Raised = t1.Date_Raised  
left join 
    (select to_char(to_date(Date_Raised,sum(Comsumed_Quantity) as product2 tableB  
        where category_id = 'Product#2'
        group by to_char(to_date(Date_Raised,'mon-yyyy')) p2
    on p2.Date_Raised = t1.Date_Raised
group by to_char(to_date(Date_Raised,'mon-yyyy')

通过使用ROW_NUMBER（）OVER（PARTITION BY ORDER BY）作为RN，可以删除重复的行。作为最终结果，您应该从日期中提取月份并使用数据透视表来实现。

我会这样：

select to_char(date_raised,'YYYY-MM'),(sum(case when product = 'Product#1' then defect_quantity end) /
        sum(case when product = 'Product#1' then consumed_quantity end)
       ) as product1,(sum(case when product = 'Product#2' then defect_quantity end) /
        sum(case when product = 'Product#2' then consumed_quantity end)
       ) as product2        
from ((select date_raised,product,defect_quantity,0 as consumed_quantity
       from a
      ) union all
      (select date_raised,0 as defect_quantity,consumed_quantity
       from b
      )
     ) ab
group by to_char(date_raised,'YYYY-MM')
order by min(date_raised);

（我更改了日期格式，因为我更喜欢YYYY-MM，但这与逻辑无关。）

为什么我更喜欢这种方法？这将包括所有个月，其中任一表中都有一行。我不必担心会无意中滤除某些月份，因为一个月内会出现生产缺失或缺陷。