查找小於平均值的計算比率（SQL）

Question

SELECT 
    PlayerName, ROUND(SUM(A)/SUM(TO),2) AS ATORatio 
FROM 
    Players_t 
INNER JOIN 
    GameStats_t ON Players_t.JerseyNumber=GameStats_t.JerseyNumber 
WHERE 
    ATORatio < (SELECT SUM(A)/SUM(TO) FROM GameStats_t) 
GROUP BY 
    PlayerName; 

我需要返回所有比ATORatio小於平均值的玩家。爲什麼這個代碼不工作？

Answer 1

下面應該有所幫助：

SELECT 
    PlayerName, ROUND(SUM(A)/SUM(TO),2) AS ATORatio 
FROM 
    Players_t 
INNER JOIN 
    GameStats_t ON Players_t.JerseyNumber=GameStats_t.JerseyNumber 
GROUP BY 
    PlayerName; 
HAVING    ----> You can also use WHERE here 
    ROUND(SUM(A)/SUM(TO),2) < (SELECT SUM(A)/SUM(TO) FROM GameStats_t) 

的問題是，ATORatio會在執行WHERE或HAVING子句不最初稱爲。因此，您需要在where或having子句中使用字段ATORatio的值。