Kbase P161704: How to distinguish the unknown value from the question mark character in ABL/4GL comparison expressi
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
13/12/2010 |
|
Status: Verified
GOAL:
How to distinguish the unknown value from the question mark character in ABL/4GL comparison expressions
GOAL:
How to use the unknown value in a comparison expression
GOAL:
How to check for the unknown value in ABL/4GL
GOAL:
How to check for null values in ABL/4GL
GOAL:
How to compare values to "?" in ABL/4GL
GOAL:
How to tell a question mark from the unknown value in a comparison expression
FACT(s) (Environment):
All Supported Operating Systems
Progress/OpenEdge Product Family
FIX:
To refer to the unknown (null) value in a comparison operation, use the character "?" (question mark) without any quotation marks. For example:
IF myVariable = ? THEN DISPLAY "This value is unknown".
To refer to the question mark character rather than the unknown value, enclose it in single or double quotes. For example:
IF myVariable = '?' THEN DISPLAY "This is a question mark".
IF myvariable = "?" THEN DISPLAY "This is a question mark".