On Mon, 28 Oct 2002, Josh Berkus wrote:
> Odd question: I have a query that returns a set of none to several rows. One
> column in these rows is BOOLEAN. I want the query to return:
> 1) TRUE if *any* of the BOOLEAN values is TRUE;
> 2) FALSE if *all* of the BOOLEAN values are FALSE;
> 3) FALSE or NULL if no rows are returned.
>
> I thought that I could do this through a MAX(boolean), but as it turns out,
> MAX(boolean) has not been defined in the standard 7.2.3. distro. I could
> define MAX(boolean), but I'm wondering if I'm missing something obvious.
Well, you might be better off making a max(bool), but a not
super-efficient version might be:max(case when col then 1 else 0 end)=1