Question

我在三个表之间使用连接查询。我的查询并未完全显示我想要的结果。有三个表team，school和game。例如，如何显示劳伦斯北高中（school_id = 11111）的总胜数？

当前查询：

SELECT school.school_name 
FROM school 
INNER JOIN team ON school.school_id = team.school_id 
INNER JOIN game ON team.team_id = game.game_id 
WHERE school.school_id = 11111

使用的表：

SQL> Select * From Team;

   TEAM_ID   SPORT_ID  SCHOOL_ID TEAM_NAME
---------- ---------- ---------- ----------
         1          1      11111 WildCats
         2          2      11111 WILDCATS
         3          3      11111 WildCats
         4          4      11111 WILDCATS
         5          5      11111 WildCats
         6          6      11111 WildCats
         7          7      11111 WildCats
         8          1     123134 Bears
         9          2     123134 Bears
        10          3     123134 BEARS
        11          4     123134 Bears
        12          5     123134 Bears
        13          6     123134 BEars

SQL> Select * From School;

 SCHOOL_ID SCHOOL_NAME                   SCHOOL_TYPE
---------- ----------------------------- ------------
     11546 Ivy Tech College              COLLegE
     11090 LAWRENCE Central Grade School GRADE SCHOOL
     11111 Lawrence NORTH High School    HIGH SCHooL
     19283 Howe High SCHOOL              High SchooL
    123134 Lawrence Central High School  HIGH SCHOOL
       192 Little Big Horn Grade School  GRADE SCHOOL


SQL> Select * From Game;

   TEAM_ID GAME_DATE R
---------- --------- -
         1 10-SEP-98 w
         1 12-SEP-98 W
         2 17-SEP-98 w
         2 18-SEP-98 W
         3 18-SEP-98 w
         3 11-SEP-98 W
         4 20-SEP-98 L
         4 21-SEP-98 l
         5 21-SEP-98 L
         5 19-SEP-98 l
         6 26-SEP-98 L
         6 27-SEP-98 W
         7 28-SEP-98 w
         7 29-SEP-98 W
         8 11-OCT-98 W
         8 12-OCT-98 w
         9 13-OCT-98 L
         9 14-OCT-98 L
        10 14-OCT-98 L
        11 15-OCT-98 L
        12 16-OCT-98 W
        13 17-OCT-98 W
        11 18-OCT-98 W
        12 19-OCT-98 W
        13 11-NOV-98
        11 12-NOV-98

Answer 1

试试这个

SELECT count(*) as Total_wins FROM school INNER JOIN team ON school.school_id = team.school_id INNER JOIN game ON team.team_id = game.game_id WHERE school.school_id = 11111 and game.r = 'W'

Answer 2

您可以在COUNT上使用Where Group By条与schoolname一起使用。

SELECT school.school_name, COUNT(game.R) as TotalWins
FROM school INNER JOIN team 
       ON school.school_id = team.school_id 
    INNER JOIN game 
       ON team.team_id = game.game_id 
WHERE 
   school.school_id = 11111 
   AND game.R = 'W'

如果你是为一所学校做的，你可以删除Group By，但如果你想获得所有学校的计数，你需要应用Group By并删除Chool_id从Where子句过滤。

Answer 3

您还必须在where子句中指定运动ID。

where school.school_id = 11111 and 
    team.sportid = (what ever the sport id you want to see)

JOIN 3表和COUNT表示结果

3 个答案: