SQL: UDF limitation

[rob@xxxxxxxxx]

I am getting quite enamored of UDF's in SQL.

The following statement works:
SELECT CCUST, CPHON,
FAXA(CPHON),
FAXAREACODE(FAXA(CPHON)),
FAXEXCHANGE(FAXA(CPHON))
FROM ROB/RCMDAT

The following doesn't:
SELECT CCUST, CPHON,
FAXA(CPHON) as FaxNumber,
FAXAREACODE(FaxNumber) as AreaCode,
FAXEXCHANGE(FaxNumber) as Exchange
FROM ROB/RCMASH
Column FAXNUMBER not in specified tables.

The following works:
SELECT CCUST, CPHON,
FAXA(CPHON) as FaxNumber,
FAXAREACODE(FAXA(CPHON)) as AreaCode,
FAXEXCHANGE(FAXA(CPHON)) as Exchange
FROM ROB/RCMASH

Not that it is a show stopper, but I am just trying to pretty it up.  Is
there something I can do to get the desired prettiness?

Rob Berendt
--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
Benjamin Franklin