|PL/SQL User's Guide and Reference
Release 2 (9.2)
Part Number A96624-01
PL/SQL Language Elements, 31 of 52
NULL statement explicitly specifies inaction; it does nothing other than pass control to the next statement. In a construct allowing alternative actions, the
NULL statement serves as a placeholder. For more information, see "NULL Statement".
NULL statement improves readability by making the meaning and action of conditional statements clear. It tells readers that the associated alternative has not been overlooked, but that indeed no action is necessary.
Each clause in an
IF statement must contain at least one executable statement. The
NULL statement meets this requirement. So, you can use the
NULL statement in clauses that correspond to circumstances in which no action is taken. The
NULL statement and Boolean value
NULL are unrelated.
In the following example, the
NULL statement emphasizes that only salespeople receive commissions:
In the next example, the
NULL statement shows that no action is taken for unnamed exceptions: