Re: doverlaps() returns null

On May 20, 1:39 pm, "Andrus" <kobrule...@hot.ee> wrote:
> I need to check when two date intervals overlap.
> Some date interval values may be null.
>
> I created the following function but
>
> select doverlaps( null, null, null, null);
>
> returns null.
>
> How to fix this so that null values are allowed in parameters ?
>
> Andrus.
>
> -- returns true when date interval $1 .. $2  overlaps with $3 .. $4
> -- null values are allowed in parameters.
> CREATE OR REPLACE FUNCTION public.doverlaps(date,
>         date, date, date, out bool) immutable AS
> $_$
> SELECT coalesce($1, timestamp '-infinity'::date)  <=coalesce($4, timestamp
> 'infinity'::date) AND
>      coalesce($2, timestamp 'infinity'::date)>=coalesce($3, timestamp
> '-infinity'::date);
> $_$ language sql;

You cannot cast +/- infinity timestamp to date, but you can cast date
to timestamp.

And what's wrong with OVERLAPS? e.g. :

CREATE OR REPLACE FUNCTION
PUBLIC.DOVERLAPS
(DATE, DATE, DATE, DATE, OUT BOOL)
IMMUTABLE AS
$_$
SELECT
(COALESCE($1::TIMESTAMP, TIMESTAMP '-INFINITY')
 , COALESCE($2::TIMESTAMP, TIMESTAMP 'INFINITY')
 )
OVERLAPS(
         COALESCE($3::TIMESTAMP, TIMESTAMP '-INFINITY')
         , COALESCE($4::TIMESTAMP, TIMESTAMP 'INFINITY'));
$_$ LANGUAGE SQL;

t=# SELECT doverlaps( NULL, NULL, NULL, NULL);
 doverlaps
-----------
 t