NVL

 =NVL Function = = =

NVL(expression, value_if_null)
The expression is the column of the table that contain a null value. The value_if_null is the character string or number that is to replace the null value within the table. The value_if_null is put like this 'number'.


This NVL function allows us to convert a null value to a known or fixed date, character or number. When converting the a null value, the argument must be convert into the same type. This allow us to do arithmetric calculation with null value because it can convert a null value to be a number to aviod getting a null solution.


 * NVL(manager_id,'0') ||
 * 19 ||
 * 19 ||
 * 0 ||





 * NVL(commission_pct,'0') ||
 * .0 ||
 * .0 ||
 * .0 ||
 * .0 ||
 * .0 ||
 * .2 ||
 * .3 ||
 * .2 ||
 * .15 ||

FROM employees

 * NVL(department_id,'0') ||
 * 90 ||
 * 90 ||
 * 90 ||
 * 10 ||
 * 110 ||
 * 110 ||
 * 80 ||
 * 80 ||
 * 80 ||
 * 0 ||