DISTINCT OR GROUP BY語句不刪除重複項？

Question

我想要做的是將所有的客戶賬單合併爲一個，因此，而不是「鯨魚市場」三次提出不同的價值，我希望「鯨魚市場有一個總價值，總數爲25968.75

我嘗試使用DISTINCT和GROUP BY不顯示任何重複的值

DISTINCT：

SELECT DISTINCT CLIENTNAME AS "Client", HOURSWORKED*CHARGERATE AS "Total Billable" 
FROM EMPLOYEE 
WHERE CLIENTNAME IS NOT NULL 
ORDER BY "Total Billable" DESC; 

GROUP BY：

SELECT CLIENTNAME AS "Client", HOURSWORKED*CHARGERATE AS "Total Billable" 
FROM EMPLOYEE 
WHERE CLIENTNAME IS NOT NULL 
GROUP BY CLIENTNAME, HOURSWORKED*CHARGERATE 
ORDER BY "Total Billable" DESC; 

種

兩種方法都給出相同的輸出：

Client            Total Billable 
------------------------- --------------------------------------- 
Whale Mart            19868.75 
Flitter              11271 
Acme Corp.            9067.375 
Flitter              8625 
Astro Electric.            5500 
Acme Corp.             4000 
Lighting Unlimited           3675 
Whale Mart             3200 
ABM Systems            3106.75 
Whale Mart             2900 
ABC Logistics            2600 
Acme Corp.             2475 
Astro Electric            2312 
Flitter              1845 
ABM Systems             1005 
ABC Logistics             900 
Speedy Messengers            375 
ABC Logistics             345 
Durham Tiles             300 
ABM Systems             160 

20 rows selected 

Answer 1

您可能需要使用聚合函數：

SELECT CLIENTNAME AS "Client", SUM(HOURSWORKED*CHARGERATE) AS "Total Billable" 
FROM EMPLOYEE 
WHERE CLIENTNAME IS NOT NULL 
GROUP BY CLIENTNAME 
ORDER BY "Total Billable" DESC; 

Answer 2

您需要：

SELECT CLIENTNAME AS "Client", SUM(HOURSWORKED*CHARGERATE) AS "Total Billable" 
FROM EMPLOYEE 
WHERE CLIENTNAME IS NOT NULL 
GROUP BY CLIENTNAME 
ORDER BY "Total Billable" DESC;