SET PLAN
SET PLAN [ON | OFF]
This command determines whether isql displays the plan used to access the data for each statement executed.By default, ISQL does not display the plan.As with many other commands, not providing a parameter toggles the current state.
SQL> set plan on;
SQL> select emp_no, first_name, last_name
CON> from employee
CON> where emp_no = 107;
PLAN (EMPLOYEE INDEX (RDB$PRIMARY7))
EMP_NO FIRST_NAME LAST_NAME
======= =============== ====================
107 Kevin Cook
SQL> update employee
CON> set first_name = 'Norman'
CON> where last_name = 'Cook';
PLAN (EMPLOYEE INDEX (NAMEX))
SQL> select count(*) from employee;
PLAN (EMPLOYEE NATURAL)
COUNT
============
42
The execution plan is displayed before the output of a select statement.