>
> 1:01:01
> 0:25:15
> 7:09:01
> 8:09:05
>
> Is there any way to average or sum those above values using a
> function?
>
> i could not type cast the varchar(40) to interval type.
>
> How to change the datatype of field from varchar to interval?
>
Try
SELECT CAST(CAST (t2 AS TEXT) AS INTERVAL) FROM test;
SELECT AVG(CAST(CAST (t2 AS TEXT) AS INTERVAL)) FROM test;
SELECT SUM(CAST(CAST (t2 AS TEXT) AS INTERVAL)) FROM test;
It works fine on my machine, I'm using PostgreSQL 7.2.1.
Regards, Christoph