Re: Single Table Report With Calculated Column

Rich Shepard wrote
> I've read some on table partitioning and using nested select statements
> with group by, but have not found the syntax to produce the needed
> results.
>
> From a table I extract row counts grouped by three columns:
>
> select stream, sampdate, func_feed_grp, count(*) from benthos group
> by stream, sampdate, func_feed_grp order by stream, sampdate,
> func_feed_group;
>
> And I want to include the proportion of each count based on the total rows
> for each stream and sampdate. The totals are obtained with this statement:
>
> select stream, sampdate, count(*) as tot_cnt from benthos group by stream,
> sampdate order by stream, sampdate;
>
> What I do not know how to do is combine the two so the resulting table
> contains the columns stream, sampdate, count, proportion. I want to learn
> how to build the sub-select to get this result. Joe Celko's 'SQL for
> Smarties, 4th Ed.' has a close example in the chapter on table
> partitioning,
> but I could not apply that model to my table.

You want to use window clause/function.

Add the following to the first query, in the select-list:

Sum(count(*)) over (partition by stream, sampdate) as stream_date_total

You function counts can then be divided into this.

The count(*) is because of the outer group by
The sum(...) is the window function

You could also just put both your queries into a with/cte (2 items) and do a
normal inner join...

Or

Select ... From (first query) fq join (second query) sq on (...)

David J.

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