NULLIF problem

["Gera Mel Handumon" <geramel(dot)h(at)gmail(dot)com>]

HELLO,

I encounter an error if i use NULLIF with timestamp with time zone.
eq. dbtime=nullif(mytime,'')

i want to null the value of field DBTIME if the variable mytime=" "

DBTIME ="timestamp with time zone" datatype

error: column DBTIME is of type timestamp with time zone but _expression_ is of type text.

What should i do?

Thanks in advance...

-- 
Gera Mel E. Handumon
Application Programmer
PaySoft Solutions, Inc.
-----------------------------------------------------------------
"Share your knowledge. It's a way to achieve immortality" - Dalai Lama