Folding subtotals into query?

[Jerry LeVan]

Is is possible, via some clever sql coding ( perhaps with PL/pgsql)
to get subtotals to appear in a selection, ie

If I have a query: select * from checks order by category
I would like the have the subtotals appear (possibly in
an unused column for each "category" when the category
"breaks".

Basically I would like to meld the query:
select category, sum(amount) from checks group by category order by
category

Into the of the first select.

Thanks,

Jerry


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[Eric Ridge]

Re: Folding subtotals into query?

On Apr 18, 2004, at 2:41 PM, Jerry LeVan wrote:
[color=blue]
> Is is possible, via some clever sql coding ( perhaps with PL/pgsql)
> to get subtotals to appear in a selection, ie
>
> If I have a query: select * from checks order by category
> I would like the have the subtotals appear (possibly in
> an unused column for each "category" when the category
> "breaks".
>
> Basically I would like to meld the query:
> select category, sum(amount) from checks group by category order by
> category[/color]

I think you want to do something like this:

SELECT *, (SELECT sum(amount) FROM checks AS x WHERE x.category =
checks.category GROUP BY x.category) AS total
FROM checks
ORDER BY category;

This will give you a column named "total" for every row in checks. The
value will be the sum(amount) for the corresponding category. You'll
likely want an index on checks.category to get any level of tolerable
performance out of the query.

eric


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[Jerry LeVan]

Re: Folding subtotals into query?

Wow, much faster

Jerry

On Apr 18, 2004, at 4:20 PM, Eric Ridge wrote:
[color=blue]
> On Apr 18, 2004, at 4:07 PM, Jerry LeVan wrote:
>[color=green]
>> That does the job, for 3200 checks it does chug for a while, too bad
>> it can't remember the intermediate results :)[/color]
>
> hmm... Can do this via a left join too. Much faster:
>
> SELECT checks.*, x.sum
> FROM checks
> LEFT JOIN (SELECT category, sum(amount) AS sum FROM checks GROUP
> BY category) AS x ON x.category = checks.category
> ORDER BY category, sum
>
> eric
>[color=green]
>>
>> --Jerry
>>
>> On Apr 18, 2004, at 3:10 PM, Eric Ridge wrote:
>>[color=darkred]
>>> On Apr 18, 2004, at 2:41 PM, Jerry LeVan wrote:
>>>
>>>> Is is possible, via some clever sql coding ( perhaps with PL/pgsql)
>>>> to get subtotals to appear in a selection, ie
>>>>
>>>> If I have a query: select * from checks order by category
>>>> I would like the have the subtotals appear (possibly in
>>>> an unused column for each "category" when the category
>>>> "breaks".
>>>>
>>>> Basically I would like to meld the query:
>>>> select category, sum(amount) from checks group by category order by
>>>> category
>>>
>>> I think you want to do something like this:
>>>
>>> SELECT *, (SELECT sum(amount) FROM checks AS x WHERE x.category =
>>> checks.category GROUP BY x.category) AS total
>>> FROM checks
>>> ORDER BY category;
>>>
>>> This will give you a column named "total" for every row in checks.
>>> The value will be the sum(amount) for the corresponding category.
>>> You'll likely want an index on checks.category to get any level of
>>> tolerable performance out of the query.
>>>
>>> eric
>>>[/color]
>>[/color]
>[/color]


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[Jerry LeVan]

Re: Folding subtotals into query?

That does the job, for 3200 checks it does chug for a while, too bad
it can't remember the intermediate results :)

--Jerry

On Apr 18, 2004, at 3:10 PM, Eric Ridge wrote:
[color=blue]
> On Apr 18, 2004, at 2:41 PM, Jerry LeVan wrote:
>[color=green]
>> Is is possible, via some clever sql coding ( perhaps with PL/pgsql)
>> to get subtotals to appear in a selection, ie
>>
>> If I have a query: select * from checks order by category
>> I would like the have the subtotals appear (possibly in
>> an unused column for each "category" when the category
>> "breaks".
>>
>> Basically I would like to meld the query:
>> select category, sum(amount) from checks group by category order by
>> category[/color]
>
> I think you want to do something like this:
>
> SELECT *, (SELECT sum(amount) FROM checks AS x WHERE x.category =
> checks.category GROUP BY x.category) AS total
> FROM checks
> ORDER BY category;
>
> This will give you a column named "total" for every row in checks.
> The value will be the sum(amount) for the corresponding category.
> You'll likely want an index on checks.category to get any level of
> tolerable performance out of the query.
>
> eric
>[/color]


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[Eric Ridge]

Re: Folding subtotals into query?

On Apr 18, 2004, at 4:07 PM, Jerry LeVan wrote:
[color=blue]
> That does the job, for 3200 checks it does chug for a while, too bad
> it can't remember the intermediate results :)[/color]

hmm... Can do this via a left join too. Much faster:

SELECT checks.*, x.sum
FROM checks
LEFT JOIN (SELECT category, sum(amount) AS sum FROM checks GROUP BY
category) AS x ON x.category = checks.category
ORDER BY category, sum

eric
[color=blue]
>
> --Jerry
>
> On Apr 18, 2004, at 3:10 PM, Eric Ridge wrote:
>[color=green]
>> On Apr 18, 2004, at 2:41 PM, Jerry LeVan wrote:
>>[color=darkred]
>>> Is is possible, via some clever sql coding ( perhaps with PL/pgsql)
>>> to get subtotals to appear in a selection, ie
>>>
>>> If I have a query: select * from checks order by category
>>> I would like the have the subtotals appear (possibly in
>>> an unused column for each "category" when the category
>>> "breaks".
>>>
>>> Basically I would like to meld the query:
>>> select category, sum(amount) from checks group by category order by
>>> category[/color]
>>
>> I think you want to do something like this:
>>
>> SELECT *, (SELECT sum(amount) FROM checks AS x WHERE x.category =
>> checks.category GROUP BY x.category) AS total
>> FROM checks
>> ORDER BY category;
>>
>> This will give you a column named "total" for every row in checks.
>> The value will be the sum(amount) for the corresponding category.
>> You'll likely want an index on checks.category to get any level of
>> tolerable performance out of the query.
>>
>> eric
>>[/color]
>[/color]


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