[Database class] selecting from tables

[Paul S. Wang]

Fatima,

When doing a select, we must pay attention only to the schema and not
to the values in the tables.   Who's to say that someone will enter some
entry later,  and a query can not give the wrong results because of such
new entries.   Do you agree?

Given, the preceding point, on what basis is your question below?

Also,  please realize that Fall 2009 is not the same as 2009.

I am sending this answer to the class list so everyone understands.

Paul
> please disregard the last email
> 
> ---------- Forwarded message ----------
> From: Fatima Mosabeh <fmosabeh at kent.edu>
> Date: Thu, Sep 29, 2011 at 12:30 PM
> Subject: db HW3
> To: pwang at cs.kent.edu
> 
> 
> Dear Prof. Wang,
> 
> Can you please clarify the second point in the HW3?
> 2. Find the IDs and names of all students who have not taken any course
> offering before Fall 2009.
> 
> the Takes table includes only 2009 and 2010 year! nothing before 2009!
> 
> sincerely,
> Fatima

-- 
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 Paul S. Wang (王士弘)                      Email: pwang at cs.kent.edu            
 Dept. of Computer Science, Kent State U.   Tel: (330) 672-9051
 Kent, Ohio, USA 44242-0001                 http://www.cs.kent.edu/~pwang/ 
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