string to date conversion - Mailing list pgsql-sql

Hi,

I'm working on an existing Pg database which, please don't ask why,
stores dates as varchar attributes in the form 'YYYY/MM/DD'

I'm not allowed to modify the tables to use 'timestamp' instead,
so I'd like to convert on the fly when retrieving datas with
select.

When I do :
       select mydatefield::timestamp from mytable;       
There's an error saying that converting from varchar to date is        
not possible

How can I do this ?

Thanks in advance

Jerome Alet