是否有可能建立我的查詢只有一個選擇語句？

Question

下面是我的查詢和它的輸出。是否有可能建立我的查詢只有一個選擇語句（我有兩個在我的查詢）？它用於性能目的。

WITH GradePassFail AS (
    SELECT 
     Subject, 
     Grade, 
     CASE WHEN Grade >= 50 THEN 1 ELSE 0 END AS Pass, 
     CASE WHEN Grade < 50 THEN 1 ELSE 0 END AS Fail 
    FROM Grade_report 
) 
SELECT Subject, MAX(Grade) AS Grade, SUM(Pass) AS Pass, SUM(Fail) AS Fail 
FROM GradePassFail 
GROUP BY Subject 

Answer 1

您可以將SUM函數中執行CASE報表合格/不合格......那麼你不需要CTE：

SELECT 
    Subject, 
    MAX(Grade) Grade, 
    SUM(CASE WHEN Grade >= 50 THEN 1 ELSE 0 END) AS Pass, 
    SUM(CASE WHEN Grade < 50 THEN 1 ELSE 0 END) AS Fail 
FROM 
    Grade_report 
GROUP BY Subject 

您可以驗證此：

http://sqlfiddle.com/#!3/99cd4/7