具有相同組合鍵的兩個表格

Question

我有兩個具有相同組合鍵的表格。 以下是表

表T1

No | Date  | S_hour 
----+---------------+------- 
1 | 2012-01-01 | 8 
1 | 2012-01-02 | 8 
1 | 2012-01-03 | 8 
2 | 2012-01-01 | 8 
2 | 2012-01-02 | 8 
2 | 2012-01-03 | 8 

表T2

No | Date  | L_hour 
----+---------------+------- 
1 | 2012-01-01 | 8 
1 | 2012-01-02 | 3 
1 | 2012-01-03 | 8 
2 | 2012-01-01 | 2 
2 | 2012-01-02 | 8 
2 | 2012-01-03 | 8 

S_hour定小時，L_hour是離開小時。

在我查詢了放我想S_hour - L_hour.Following應查詢輸出提前 查詢輸出

No | Date  | S_hour - L_hour 
----+---------------+------- 
1 | 2012-01-01 | 0 
1 | 2012-01-02 | 5 
1 | 2012-01-03 | 0 
2 | 2012-01-01 | 6 
2 | 2012-01-02 | 0 
2 | 2012-01-03 | 0 

感謝

Answer 1

select t1.No 
,  t1.Date 
,  t1.S_hour - t2.L_hour 
from Table1 t1 
join Table2 t2 
on  t1.No = t2.No 
     and t1.Date = t2.Date 

Answer 2

像這樣

SELECT T1.No, T1.Date, s_hour - L_hour AS result 
FROM T1 INNER JOIN 
T2 ON t1.No = t2.No AND 
T1.Date = T2.Date 

Answer 3

SQL查詢：

SELECT t1.no, t1.date1, t1.s_hour - t2.l_hour FROM t1, t2 
WHERE t1.no=t2.no AND t1.date1=t2.date1; 

小提琴：Demo