What is the method for Oracle to determine if a field value is empty?

1 year ago
Emily Johnson
2 minutes

In Oracle, you can use the following methods to check if a field value is empty:

  1. To check for NULL values, you can use the IS NULL condition. For example, the following query returns all employee records in the table named “employees” where the “hire_date” field is empty.
  2. Show all the employees who have not been hired yet.
  3. The IS NOT NULL condition can be used to check if a field is not empty. For example, the query below retrieves all employee records in the “employees” table where the “hire_date” field is not empty.
  4. Retrieve all employees who have a hire date.
  5. Using the NVL function to determine: You can use the NVL function to replace null values with a specified value, and then make a judgment. For example, the following example query returns all employee records in the table named “employees” where the “hire_date” field is empty or a specified date.
  6. Retrieve all employees who were hired on ’01-JAN-2000′ or have a hire date of ’01-JAN-2000′ if their hire date is null.
  7. In the above example, the NVL function replaces records with empty “hire_date” fields with ’01-JAN-2000′ before comparing them to ’01-JAN-2000′.
  8. You can use a CASE expression to determine if a field value is empty. For example, the following query returns ‘Yes’ or ‘No’ based on whether the ‘hire_date’ field is empty in the table named “employees”.
  9. Check if the hire date is null and return ‘Yes’ if it is null, otherwise return ‘No’ as the value for the column named is_hire_date_null in the employees table.
  10. In the example above, the CASE expression returns ‘Yes’ if the “hire_date” field is empty, otherwise it returns ‘No’.
bannerAds