如何检查同一查询中的聚合函数的值？

Question

这MySQL查询给了我这个错误'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()聚合函数的值，但是有什么办法来检查查询中的winnings价值？

Answer 1

你可以试试：

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

无法使用内选择一个集合列。但是，在计算完所有聚合列后，可以使用子查询来获取计数器值。

如何计算计数器值？如果至少有10个奖金，则我认为该计数器应该是（奖金 - 10）/ 2，否则为0。在这种情况下，你可以用这个查询来获得它

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