Oracle SQL-如何將計數除以計數總和？

Question

我有一個查詢，當前看起來像這樣（簡體）

 SELECT
       m.academicyr,
       m.ncyeargrp_format AS YEAR,
       Count(*) AS cohort,
       round (Avg (m.per_att),4) AS attendance,
       Round (per_cohort,4)      

   FROM
 (
   SELECT
         s.academy,
         s.academicyr,
         s.adno,
         s.ncyeargrp_format,
         CASE WHEN a.possible_att_marks = 0 THEN NULL
           ELSE (a.present_att_marks / a.possible_att_marks)
             END
               AS per_att,
         a.possible_att_marks,
         a.present_att_marks,
         a.period,
         Count (*) AS cohort,
         Count (*) / Sum(Count(*)) AS per_cohort

   FROM
      VACADEMY_STU_all  s

   LEFT JOIN
        vacademy_attendance a
       ON s.academy = a.academy
      AND s.adno = a.adno
      AND s.term = a.period
      AND s.academicyr = a.academicyr

   WHERE
          s.academy = 'CAN'
          AND s.academicyr = '1617'
          AND a.period = '1'

          GROUP BY
         s.academy,
         s.academicyr,
         s.adno,
         s.ncyeargrp_format,
         a.possible_att_marks,
         a.present_att_marks,
         a.period

  ) m
          GROUP BY
          m.academicyr,
          m.ncyeargrp_format,
          m.per_cohort

          ORDER BY
          To_Number(Trim(regexp_replace(m.ncyeargrp_format, '[A-Za-z]')))

我在這里嘗試將計數*除以計數*的總和。 我收到錯誤消息“不是單個組函數”。

該查詢在沒有第一個選擇時使用'Round（Per_cohort，4）'的情況下也可以正常工作，並且也從內部選擇和分組依據中刪除。

我期望的結果是

年份組螺柱計數同類人群的百分比年份7126 18.18％98.10％年份8139 20.06％93.88％年份9143 20.63％90.56％年份10143 20.63％95.94％年份11142 20.49％88.45％總計693 100.00％93.28 ％

我的所有其他列均正常運行，我只需要對同類群組進行百分比計算，因此，同類群組列中的值除以同類群組列的總數（已使用count *創建）。

任何幫助，不勝感激。

謝謝

Answer 1

如果這是發生錯誤的行：

     Count (*) / Sum(Count(*)) AS per_cohort

然后，您可以使用窗口函數來解決此問題：

     Count (*) / Sum(Count(*)) over () AS per_cohort

Answer 2

WITH cte AS
(
    SELECT s.academy,
           s.academicyr,
           s.adno,
           s.ncyeargrp_format,
           CASE WHEN a.possible_att_marks = 0 THEN NULL
                ELSE (a.present_att_marks / a.possible_att_marks)
           END AS per_att,
           a.possible_att_marks,
           a.present_att_marks,
           a.period,
           COUNT(*) AS cohort
    FROM VACADEMY_STU_all s
    LEFT JOIN vacademy_attendance a
        ON s.academy = a.academy AND
           s.adno = a.adno AND
           s.term = a.period AND
           s.academicyr = a.academicyr
    WHERE s.academy = 'CAN' AND
          s.academicyr = '1617' AND
          a.period = '1'
    GROUP BY s.academy,
             s.academicyr,
             s.adno,
             s.ncyeargrp_format,
             a.possible_att_marks,
             a.present_att_marks,
             a.period
)

SELECT m.academicyr,
       m.ncyeargrp_format AS YEAR,
       m.cohort,
       ROUND(AVG(m.per_att), 4) AS attendance,
       ROUND(m.cohort / (SELECT SUM(cohort) FROM cte), 4)
FROM cte m
GROUP BY m.academicyr,
         m.ncyeargrp_format,
         m.per_cohort
ORDER BY TO_NUMBER(TRIM(REGEXP_REPLACE(m.ncyeargrp_format, '[A-Za-z]')))