Kbase P17746: Why Do Unknown Values Appear in Results Sets Occasionally
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
11/25/2003 |
|
Status: Unverified
GOAL:
Why Do Unknown Values Appear in Results Sets Occasionally
CAUSE:
This is caused by the index used in the query.
Unknown values are sorted high in result ranges.
When an index is used,first Progress sorts information according to the index. Then, Progress finds the first record meeting the criteria of the search & returns all the associated records after that first record.
If there is no index defined, in this example no index containing date, Progress sorts the data then looks for Records meeting the Where criteria.
In the cases of comparing a date to an unknown value (i.e. Today > ?), Progress returns an unknown value.
FIX:
The proper query to exclude unknowns would be;
FOR EACH INVOICE WHERE (INVOICEDATE > 1/1/1998 and INVOICEDATE NE ?):