如何檢查同一查詢中的聚合函數的值？

Question

這MySQL查詢給了我這個錯誤'Unknown column 'winnings' in 'field list'

SELECT 
o.user_id, 
sum(case when o.result = 1 or o.result=2 or o.result = 0 then 1 else 0 end) as tahmins_no, 
sum(case when o.result = 1 then 1 else 0 end) as winnings, 
sum(case when o.result = 2 then 1 else 0 end) as loses, 
sum(case when winnings = 10 then 0.5 else 0 end) as counter 
FROM `odds_tahminler` o 

我知道winnings是sum()聚合函數的值，但是有什麼辦法來檢查查詢中的winnings價值？

Answer 1

你可以試試：

SELECT 
o.user_id, 
sum(case when o.result = 1 or o.result=2 or o.result = 0 then 1 else 0 end) as tahmins_no, 
sum(case when o.result = 1 then 1 else 0 end) as winnings, 
sum(case when o.result = 2 then 1 else 0 end) as loses, 
sum(case when winnings = 10 then 0.5 else 0 end) as counter 
FROM `odds_tahminler` o 
GROUP BY o.user_id 
HAVING counter>2 

Answer 2

無法使用內選擇一個集合列。但是，在計算完所有聚合列後，可以使用子查詢來獲取計數器值。

如何計算計數器值？如果至少有10個獎金，則我認爲該計數器應該是（獎金 - 10）/ 2，否則爲0。在這種情況下，你可以用這個查詢來獲得它

SELECT O.*, 
     GREATEST((O.winnings - 10)/2, 0) as counter    
    FROM 
     (
      SELECT u.username, 
       o.user_id, 
       sum(case when o.result = 1 or o.result=2 or o.result = 0 then 1 else 0 end) as tahmins_no, 
       sum(case when o.result = 1 then 1 else 0 end) as winnings, 
       sum(case when o.result = 2 then 1 else 0 end) as loses 
      FROM `odds_tahminler` o 
     ) as O