Databases - Working with Null Values

How do you handle variables which have not been assigned values? For instance

c = a + b

where "a" has a value and "b" does not. Some systems generate an error, others seem to work ok.

MS Access 97

if IsNull(xx)  then
if IsEmpty(xx) then
Nz(xx)           returns either zero, or a null string - "" - or xx 
Nz(xx, yy)       returns either yy (if xx is null) or xx

Author: Robert Clemenzi - clemenzi@cpcug.org

Databases - Working with Null Values

MS Access 97

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