來自連接表的多個記錄的總和？

Question

我有這樣的查詢：

select a,b,c 
from 
table 

現在我有一個在它hoursWorked另一個表。基本上我想要anotherTable.hoursWorked其中anotherTable.a = a和anotherTable.b = b和anotherTable.c = c的總和。

我需要做什麼樣的查詢？

感謝

事情是這樣的：

SELECT DATE, CUSTOMER, SUM(FKEY.HOURSWORKED) 
FROM TABLE1 
INNER JOIN TABLE2 FKEY ON FKEY.CUSTOMER = CUSTOMER, FKEY.DATE = DATE 

Answer 1

你會寫這樣的事：

SELECT SUM(at.hoursWorked) 
FROM 
    anotherTable at 
    JOIN (SELECT a, b, c FROM thisTable) t 
    ON at.a = t.a AND at.b = t.b AND at.c = t.c 

Answer 2

修改您的例如SQL，這樣它的工作原理：

SELECT TABLE1.DATE, TABLE1.CUSTOMER, SUM(FKEY.HOURSWORKED) AS HOURSWORKED 
FROM TABLE1 
INNER JOIN TABLE2 FKEY 
ON FKEY.CUSTOMER = TABLE1.CUSTOMER AND FKEY.DATE = TABLE1.DATE 
GROUP BY TABLE1.DATE, TABLE1.CUSTOMER 

mos重要的改變是我添加了GROUP BY條款。