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Posted by Lyle Fairfield on 10/02/73 11:45
Null is not zero. Null is not a zero length string.
I believe that nulls were not designed to be placeholders for these
values.
We should be extremely careful when we convert nulls to values. Such
conversion could lead to error. Often it is persons without strong
grounding in mathematics and logic who make these conversions,
increasing the likelihood of such error. The best practice is likely to
be the exclusion of records with nulls in the columns we are processing
and to enter values in those where a value is appropriate. There may be
some cases where it's a good idea to substitute a zls for a null value,
but none comes to my mind at this time.
IMNSHO SQL would be more rigorous if it had no IsNull(Field,Value) or
corresponding Coalesce function.
[Yes, I've probably posted IsNull(Field,Value) solutions here; that was
then; this is now.]
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