TO_DATE function between PostgreSQL 8.2 and 9.4

Hi,

I have had a Perl Website working for 7 years and have had no problems

until at the weekend I replace my database server with a newer one.

Database server (old): PostgreSQL 8.2 32bit

Database server (new): PostgreSQL 9.4 64bit

I run following sql in PostgreSQL 8.2, it return my expected result as ‘YYYY-MM-DD’ format.

--PostgreSQL 8.2

---------------

SELECT to_date(now() + '-7day', 'YYYY-MM-DD');

However after i migrated to PostgreSQL 9.4, i hit following error:

--PostgreSQL 9.4

---------------

SELECT to_date(now() + '-7day', 'YYYY-MM-DD');

--------------------------------------------------------------------------------

ERROR: function to_date(timestamp with time zone, unknown) does not exist

LINE 1: SELECT to_date(now() + '-7day', 'YYYY-MM-DD')

^

********** Error **********

Of course, the most reliable way to deal with it is to

rewrite the application or SQL to handle types strictly,

but the application is large and rewrite is a terrible job.

Is there any easy way to maintain compatibility?

Regards,

--

gzh