如何在MySQL

Question

計算獨特的列值這裏是我的數據

cardNo| userName| tablename| hours | date 
1  | a  | a  | 12 | 12-06-2015 
1  | a  | a  | 5 | 11-06-2015 
2  | b  | b  | 3 | 15-06-2015 
1  | a  | a  | 8 | 12-06-2015 
2  | b  | b  | 3 | 21-06-2015 
1  | a  | a  | 12 | 14-06-2015 
2  | b  | b  | 10 | 8-06-2015 

cardNo是獨一無二的。我需要顯示每個卡上的所有細節和總小時數，如：

cardNo | userName | tablename | totalhours 
1  | a  | a  | 37 
2  | b  | b  | 16 

Answer 1

SELECT cardNo，userName，tablename，sum（hours）hours FROM Table_1 GROUP BY cardNo，userName，tablename

Answer 2

很簡單SUM()與GROUP BY：

SELECT cardNo,sum(hours) 
FROM yourtable 
GROUP BY cardNo; 

我把它作爲一個練習OP到包括用戶姓名和表名列到查詢中