Bugs item #523472, was opened at 2002-02-27 08:58
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Category: Core Engine
Group: Feature request
>Status: Deleted
Resolution: Rejected
Priority: 5
Submitted By: Fabiano Bonin (fabianobonin)
Assigned to: Ann W. Harrison (awharrison)
Summary: FIRST() and LAST() aggregate functions
Initial Comment:
select first(field2) from table1 group by field1;
select last(field2) from table1 group by field1;
FIRST should return the first occurrence of the field
and LAST, the last occurrence
to work like
select max(field2) from table1 group by field1;
select min(field2) from table1 group by field1;
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>Comment By: Sean Leyne (seanleyne)
Date: 2002-02-27 09:40
Message:
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user_id=71163
To reflect Ann decision to reject the request at this time.
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Comment By: Sean Leyne (seanleyne)
Date: 2002-02-27 09:39
Message:
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Doesn't the current SELECT FIRST x SKIP y ... FROM ...
syntax address the issue of the FIRST() function?
Accordingly, wouldn't the LAST() functionality be addressed
by a SELECT LAST x ... FROM ...? (although this seems much
more difficult to enabled)
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Comment By: Fabiano Bonin (fabianobonin)
Date: 2002-02-27 09:38
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SELECT FIRST and SELECT LAST doesn't works to the purpose i
was thinking.
I was thinking in the case of a query with a group by
clause where i need to get the first or the last value of a
non grouped field.
For example:
I have a table (invoices) with fields (id, date, number and
customer_id)
if i want to know the number of the last invoice for each
customer (based on the invoice date), i would do this:
select
customer_id,
last(number)
from
invoices
group by
customer_id
order by
date
And i will have the last invoice.number for each customer,
based on the invoice date
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Comment By: Sean Leyne (seanleyne)
Date: 2002-02-27 09:22
Message:
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user_id=71163
Doesn't the current SELECT FIRST x SKIP y ... FROM ...
syntax address the issue of the FIRST() function?
Accordingly, wouldn't the LAST() functionality be addressed
by a SELECT LAST x ... FROM ...? (although this seems much
more difficult to enabled)
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Comment By: Ann W. Harrison (awharrison)
Date: 2002-02-27 09:12
Message:
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user_id=66088
We can discuss this one on the list, but MAX and MIN provide that functionality.
Yes, you can use MAX and MIN on character datatypes. If you're asking for
a positional function rather than a value-based comparison, I have a great deal
of trouble with that concept because position isn't a relational concept and the
introduction of positional operators will signficantly inhibit efforts to improve
performance by performing operations in parallel.
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