案情總結

Question

下面的SQL返回“無法對包含聚合或子查詢的表達式執行聚合函數。”，有人可以幫忙嗎？

SELECT 
sum(case when Frequency = 'Monthly' then ISNULL(SUM(Amount),0.0) else 0 end) + 
sum(case when Frequency = '4 Weekly' then ISNULL(SUM(Amount),0.0) / 2 else 0 end) +
sum(case when Frequency = 'Fortnightly' then ISNULL(SUM(Amount),0.0) / 3 else 0 end) +
sum(case when Frequency = 'Weekly' then ISNULL(SUM(Amount),0.0) / 5 else 0 end) 
FROM TableWHERE Id = 1

Answer 1

如果需要條件聚合，則只需要一個sum() ：

SELECT sum(case when Frequency = 'Monthly' then Amount else 0 end) + 
       sum(case when Frequency = '4 Weekly' then Amount / 2 else 0 end) +
       sum(case when Frequency = 'Fortnightly' then Amount / 3 else 0 end) +
       sum(case when Frequency = 'Weekly' then Amount,0.0) / 5 else 0 end) 
FROM Table
WHERE Id = 1;

Answer 2

我想你想做些類似的事情

sum(case when Frequency = 'Monthly' then ISNULL(Amount,0.0) else 0 end)

Answer 3

SELECT 
sum(case when Frequency = 'Monthly'     then ISNULL(Amount,0.0)     else 0 end) + 
sum(case when Frequency = '4 Weekly'    then ISNULL(Amount,0.0) / 2 else 0 end) +
sum(case when Frequency = 'Fortnightly' then ISNULL(Amount,0.0) / 3 else 0 end) +
sum(case when Frequency = 'Weekly'      then ISNULL(Amount,0.0) / 5 else 0 end) 
FROM Table
WHERE Id = 1