postalcodes have timezone

number of errors=3
number of warnings=0
Group=chkGrpPostalCode
Group=chkGrpTimezone

select countrycode,count(*) as cnt from zip_code where timezoneid is null group by countrycode order by countrycode

update zip_code set timezoneid=t.timezoneid from geoname_timezone t where zip_code.timezoneid is null and t.countrycode=zip_code.countrycode and t.layer=2 and st_within(zip_code.geography::geometry,wkb_geometry);

countrycode	cnt	
AU	4	
CA	900678	
US	501