有人能指出我正确的方向来消除学生ID字段中的重复吗?
SQL> select DISTINCT(student_class.student_id) as student_Num,student_class.class_id,
2 event.event_id, event.event_name
3 from student_class, event
4 where student_class.class_id = '10'
5 and event.class_id = '10';
STUDENT_NUM CLASS_ID EVENT_ID EVENT_NAME
----------- ---------- ---------- --------------------------------------------------
12 10 2 Flag FOOtball Game
12 10 5 PICKUP SOCCER GAME
9 10 5 PICKUP SOCCER GAME
16 10 5 PICKUP SOCCER GAME
6 10 2 Flag FOOtball Game
18 10 5 PICKUP SOCCER GAME
4 10 5 PICKUP SOCCER GAME
4 10 2 Flag FOOtball Game
16 10 2 Flag FOOtball Game
20 10 2 Flag FOOtball Game
3 10 5 PICKUP SOCCER GAME
2 10 5 PICKUP SOCCER GAME
3 10 2 Flag FOOtball Game
8 10 2 Flag FOOtball Game
9 10 2 Flag FOOtball Game
2 10 2 Flag FOOtball Game
6 10 5 PICKUP SOCCER GAME
20 10 5 PICKUP SOCCER GAME
18 10 2 Flag FOOtball Game
8 10 5 PICKUP SOCCER GAME
答案 0 :(得分:0)
尝试 SQL>
SELECT DISTINCT event.event_id,event.event_name,COUNT(student_class.student_id) AS 'Total Students'
FROM student_class, event
WHERE student_class.class_id = '10'
AND event.class_id = '10'
GROUP BY event.event_id,event.event_name,student_class.student_id
这应该为您提供活动ID和姓名,其中包含数字的学生。