Help with query involving aggregation and joining.
От | Eddie Cheung |
---|---|
Тема | Help with query involving aggregation and joining. |
Дата | |
Msg-id | 20030223190227.21867.qmail@web80401.mail.yahoo.com обсуждение исходный текст |
Ответы |
Re: Help with query involving aggregation and joining.
Re: Help with query involving aggregation and joining. |
Список | pgsql-sql |
Hi, I have not been able to construct an SQL statement for my task. What seemed like a simple query turned out to be beyond my capability. Any help will be very much appreciated. My requirements involve several large tables. I have simplied scenario into the follow two fictional tables which describes the same requirements. HISTORY ======= id | courseId | submission ---+-----------+-------------1 | 101 | 2002-01-20 2 | 102 | 2002-02-173 | 104 | 2002-04-304 | 102 | 2002-02-225 | 104 | 2002-03-156 | 104 | 2002-01-21 COURSE ====== id | name ------+----------- 101 | Physics 102 | Chemistry 103 | Biology 104 | Maths 105 | English Basically I would like to display the latest submission for each course in a table as shown below, order by name of the courses. Query Results: ==============id | courseId | name | submission ---------------------------------------4 | 102 | Chemisty | 2002-02-223 | 104 | Maths | 2002-04-301 | 101 | Physics | 2002-01-20 I have tried many different approach but all failed... Thanks a lot for your help. Regards, Eddie __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com
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