SQL連接未正常工作旺旺

Question

我有兩個表像

洛表

+-------------+---------+---------+-----+ 
| player_name | user_id | tour_id | los | 
+-------------+---------+---------+-----+ 
| P1   |  1 |  3 | 1 | 
| P2   |  1 |  3 | 3 | 
| P3   |  1 |  3 | 2 | 
| P4   |  1 |  3 | 2 | 
| P5   |  1 |  3 | 2 | 
| P6   |  1 |  3 | 1 | 
| P7   |  1 |  3 | 1 | 
| P8   |  1 |  3 | 0 | 
+-------------+---------+---------+-----+ 

而且

運表

+-------------+---------+---------+-----+ 
| player_name | user_id | tour_id | win | 
+-------------+---------+---------+-----+ 
| P1   |  1 |  3 | 2 | 
| P2   |  1 |  3 | 0 | 
| P3   |  1 |  3 | 1 | 
| P4   |  1 |  3 | 1 | 
| P5   |  1 |  3 | 1 | 
| P6   |  1 |  3 | 2 | 
| P7   |  1 |  3 | 2 | 
| P8   |  1 |  3 | 3 | 
+-------------+---------+---------+-----+ 

而且我想球員姓名，洛杉磯從第一，從第二贏得

我想集團被球員的名字，但它會出現誤導結果

select player_name, los.los, win.win 
from los,win 
group by player_name; 

Answer 1

只要你加入，必須有一個加盟條件否則它會做一個笛卡爾乘積。

select los.player_name, sum(los.los), sum(win.win) 
from los,win 
where los.player_name = win.player_name 
group by los.player_name;