The following table shows the typical elements in logical expressions that use SQL records:
First operand | Comparison Operator | Second operand |
---|---|---|
field in SQL record | One of these:
|
One of these:
The trunc test can resolve to true only when the database column is longer than the field. The value for the test is false after a value is moved to the field or after the field is set to null. |
field in SQL record | One of these:
|
NULL. Keyword for testing whether the field was set to a null value, either by an assignment statement or by reading from a relational database |