Oracle中如何用子查询/派生表统计GROUP BY结果的I_Count总和

Alright, since you're aiming to retrieve only the total sum of I_Count (which comes out to 10 based on your grouped results) and you've already endorsed Gordon Linoff's approach, here's how to wrap your existing GROUP BY query into a derived table to achieve this:

SELECT SUM(I_Count) AS Total_I_Count
FROM (
    -- Your original GROUP BY query as a derived table
    SELECT I_Count, I_Number, I_Letter 
    FROM table 
    GROUP BY I_Count, I_Number, I_Letter
) AS GroupedResults;

How this works: #

• The inner query is your original GROUP BY statement, which generates the grouped results you shared:

  I_Count | I_Number | I_Letter
  4 | 100 | A
  5 | 101 | B
  1 | 102 | C

• The outer query takes this derived table (GroupedResults) and uses the SUM() aggregate function on the I_Count column, adding up 4 + 5 + 1 to get the total sum of 10.
• Since your requirement is to only get this total, the outer query returns exactly that single value without any extra columns.

内容的提问来源于stack exchange，提问作者Joseph