The DO statement is
the simplest form of DO group processing. The statements between the
DO and END statements are called a
DO group. You can nest DO statements within DO groups.
Note: The memory capabilities of
your system can limit the number of nested DO statements that you
can use. For details, see the SAS documentation about how many levels
of nested DO statements your system's memory can support.
A simple DO statement
is often used within IF-THEN/ELSE statements to designate a group
of statements to be executed depending on whether the IF condition
is true or false.