SQL的總和部門

Question

你好，我正在計算根據校園地點的學生的某些小時的百分比..所以我將他們學期的總小時數並試圖將它除以僅從該校園中獲得的小時數想出一個大概比例的主校園。

例如，如果他們班的80％發生在校園A，那麼我可以使用它。我改變了表名，因爲他們是明顯的原因

這是我一直在嘗試，似乎無法使其工作。任何提示/建議

select "credits_sum"/"div_hours" 
from table1 
where credits_sum = (select sum(credit_hr) 
      from table1 
      where table1_term_code = 201480 
      and table1_rsts_code not like 'D%' 
      and table1_id = 1234) 

and div_hours = (select sum (credit_hr) 
       from table1 
       where table1_id = 1234 
       and table1_TERM_CODE = 201480 
       and table1_RSTS_CODE not like 'D%' 
       and table1_RSTS_CODE not like 'W%' 
       and table1_CAMP_CODE = 'PPE' 
       and table1_CREDIT_HR > 0 
       group by table1_id); 

Answer 1

你會想要使用CASE語句來關閉它。你現在在做什麼，你的WHERE條款只是限制整個記錄基於其他選擇的總和......並沒有任何意義。

我懷疑你想要的東西是一樣的東西：

SELECT 
    SUM(CASE WHEN table1_term_code = 201480 
      and table1_rsts_code not like 'D%' 
      and table1_id = 1234 THEN credit_hr END) 
     /
    SUM(CASE WHEN table1_id = 1234 
       and table1_TERM_CODE = 201480 
       and table1_RSTS_CODE not like 'D%' 
       and table1_RSTS_CODE not like 'W%' 
       and table1_CAMP_CODE = 'PPE' 
       and table1_CREDIT_HR > 0 THEN credit_hr END) AS divisionField 
from table1