2012-04-17 83 views
-4

打印该级别的学生和平均年龄,除JR以外的所有级别。我想写mysql查询

CREATE TABLE STUDENT (
    sid NUMERIC(6) NOT NULL, 
    sname VARCHAR(15), 
    major VARCHAR(20), 
    level VARCHAR(2), 
    sage NUMERIC(2) NOT NULL, 
    PRIMARY KEY (sid) 
); 

INSERT INTO STUDENT (sid, sname, major, level, sage) values (1,'JOHN','EE','FR' ,18); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (2,'TIM','EE','FR',19); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (3,'RICHARD','EE','SO',20); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (4,'EDWARD','EE','SO',21); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (5,'ALBER','CS','JR',22); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (6,'MARY','EE','JR',22); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (7,'JACK','EE','SR',23); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (8,'JULIAN','EE','SR',22); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (9,'SAM','EE','SR',24); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (10,'RAM','CS','SR',23); 
INSERT INTO STUDENT (sid, sname, major, level, sage) values (11,'RICK','EE','SR',24); 
+5

新加坡国立大学医院嗯。你写它,然后回来一个具体的问题。 – simchona 2012-04-17 18:07:46

+1

你应该真的显示你已经尝试过 – wickedone 2012-04-17 18:13:39

回答

2
SELECT level, AVG(sage) AS AvgAge 
    FROM STUDENT 
    WHERE level != 'JR' 
GROUP BY level 
+0

+1更快的回答 – wickedone 2012-04-17 18:13:01

+0

+0以闪电般的速度给那个人一条鱼! – hexparrot 2012-04-17 18:14:07

+0

@hexparrot我想我感觉很慷慨。 :) – Taryn 2012-04-17 18:16:24

0
SELECT level, AVG(sage) 
    FROM STUDENT 
    WHERE level <> 'JR' 
    GROUP BY level