NULL VALUES
I have a tableA table in a database called DBA, with this dbschema:
create table tableA
( fieldA char(2),
fieldB char(2),
fieldC date )
And the values of two rows are:
row 1 ---> 12 AC 12/01/98
row 2 ---> 12 DN
I have this 4gl program:
----------------------------------------
database DBA
define r record like tableA.*
main
select * INTO r.*
from fimovi where fieldA="12" and fieldB="AC"
IF status=NOTFOUND THEN
display "NOTFOUND"
ELSE
IF r.fieldC<>" " THEN
display "FOUND WITH date: ", r.fieldC
END IF
END IF
end main
-------------------------------
when I execute the program, it is displayed " FOUND WITH date 12/01/98".
IF i change the select in my 4gl program,
select * INTO r.*
from fimovi where fieldA="12" and fieldB="AC"
and fieldC<>" "
the execution of the program displays "NOTFOUND".
My sistem have:
INFORMIX-4GL Version 7.20.UD1
INFORMIX-SQL Version 7.20.UD1
Why the difference?