Thanks

Thanks all for the help :)
 I got to do all this, because there a existing system
running on SQL Server/SQL Anyway which using
all these syntax though out the coding, and I got to
make it support postgreSQL
 And here is a question relate to the DataDiff function
in SQL Server, is it possible to write a function that pass
the parameter like the DataDiff function, I mean:

DataDiff( Year, date1, date2)
but not
DataDiff( 'Year', date1, date2)

Is it possible to doing this? Define a enum data type?

Thanks
Bill