From: | Frank Bax <fbax(at)sympatico(dot)ca> |
---|---|
To: | <pgsql-sql(at)postgresql(dot)org> |
Subject: | Re: simple? join |
Date: | 2002-01-07 22:08:28 |
Message-ID: | 3.0.6.32.20020107170828.0099e8b0@pop6.sympatico.ca |
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Lists: | pgsql-sql |
At 12:22 AM 1/6/02 -0500, Peter Eisentraut wrote:
>Frank Bax writes:
>> EMPLOYEE table contains: emp, first, last (emp is unique key)
>> TIMESHEET table contains: emp, timestamp, hours
>> I want to report employee name and total hours.
>> SELECT first, last, sum(ts.hours)
>> FROM timesheet ts, employee emp
>> WHERE ts.emp = emp.emp
>> GROUP by emp.emp, first, last
>> ORDER BY last, first;
>>
>> It seems silly to specify extraneous "group by" fields.
>
>There's nothing "extraneous" there. Both first and last could be
>duplicated, so you need to group by each one.
But first and last can't be duplicated if emp is defined as unique. If I
am also selecting a dozen or so other fields from "employee" table, must I
also include them all in the GROUP BY clause, even though I know "emp"
identifies a unique row in this table?
Frank
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