Kbase P50250: Oracle dataserver and comparison with ? (unknown value)
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
16/10/2008 |
|
Status: Unverified
GOAL:
ORACLE and comparison with unknown values
FIX:
The Progress unknown value (?) satisfies only the equals(=) operator, translated into Oracle as "IS NULL".
When used with a different logical operator (GT, LT, ...), you do not get a reliable result.
You will get an error "illegal operator for unknown value or zero length character string" when the comparison is made with a character datatype.