In PLSQL to check if a value is not null, you must use the "IS NOT NULL" syntax.
For example,
IF Lvalue IS NOT NULL then ... END IF;
If Lvalue does not contain a null value, the "IF" expression will evaluate to TRUE.
You can also use "IS NOT NULL" in an SQL statement. For example:
select * from suppliers where supplier_name IS NOT NULL;
This will return all records from the suppliers table where the supplier_name does not contain a null value.
