需要幫助設計一個合適的SQL查詢

Question

我有這個表：

DebitDate | DebitTypeID | DebitPrice | DebitQuantity 
---------------------------------------------------- 
40577  1    50   3 
40577  1    100   1 
40577  2    75   2 
40578  1    50   2 
40578  2    150   2 

我想用一個單一的查詢來獲取（如果可能的話），這些細節： 日期，debit_id，total_sum_of_same_debit，how_many_debits_per_day

所以從上面的例子中我會得到：

40577, 1, (50*3)+(100*1), 2 (because 40577 has 1 and 2 so total of 2 debits per this day) 
40577, 2, (75*2), 2 (because 40577 has 1 and 2 so total of 2 debits per this day) 
40578, 1, (50*2), 2 (because 40578 has 1 and 2 so total of 2 debits per this day) 
40578, 2, (150*2), 2 (because 40578 has 1 and 2 so total of 2 debits per this day) 

所以我有這樣的SQL查詢：

SELECT  DebitDate, DebitTypeID, SUM(DebitPrice*DebitQuantity) AS TotalSum 
FROM  DebitsList 
GROUP BY DebitDate, DebitTypeID, DebitPrice, DebitQuantity 

現在我有麻煩了，我不確定在哪裏把我需要的最後信息的計數。

Answer 1

你需要一個相關的子查詢來獲得這個新的列。您還需要通過GROUP BY子句刪除 DebitPrice和DebitQuantity以使其生效。

SELECT DebitDate, 
     DebitTypeID, 
     SUM(DebitPrice*DebitQuantity) AS TotalSum, 
     ( select Count(distinct E.DebitTypeID) 
      from DebitsList E 
      where E.DebitDate=D.DebitDate) as CountDebits 
FROM  DebitsList D 
GROUP BY DebitDate, DebitTypeID 

Answer 2

我認爲這可以幫到你。

SELECT  DebitDate, SUM(DebitPrice*DebitQuantity) AS TotalSum, Count(DebitDate) as DebitDateCount 
FROM  DebitsList where DebitTypeID = 1 
GROUP BY DebitDate