Re: SQL Question - Using Group By

> Hi,
>
> I have a question about using Group By.
>
> On a table like this:
>
> Type (varchar) | Active (boolean)
> --------------------------------------------------------
> Type One | False
> Type Two | True
> Type One | True
> Type Fifty | Flase
> Type Two | True
>
> Having this table I want a report grouping Types and giving me more
> statistics such as:
>
> Type | Active Count | Inactive Count | Active
> Percent
>
> How do i do that?
>
> I can think of :
>
> select Type from table_name group by Type
>
This should been quite easy - the trick is aggregate functions omit NULL
values (maybe there is some other / better way):

SELECT type,
COUNT(CASE WHEN active THEN 1 ELSE NULL END) AS active_count,
COUNT(CASE WHEN active THEN NULL ELSE 1 END) AS
inactive_count,
COUNT(CASE WHEN active THEN 1 ELSE NULL END) / COUNT(*)
AS active_pct
FROM table_name;

but have not tested it ;(

Tomas