Folding subtotals into query?

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

--Jerry

On Apr 18, 2004, at 3:10 PM, Eric Ridge wrote:

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

On Apr 18, 2004, at 4:07 PM, Jerry LeVan wrote:

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

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

--Jerry

On Apr 18, 2004, at 3:10 PM, Eric Ridge wrote:

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