Oracle’s EXPLAIN PLAN
 
 
- To generate a plan:
- 
 EXPLAIN PLAN SET STATEMENT_ID = 'Emp_Sal’ FOR 
 
 SELECT ename, job, sal, dname
 FROM emp, dept
 WHERE emp.deptno = dept.deptno
 AND NOT EXISTS
 (SELECT * FROM salgrade
 WHERE emp.sal BETWEEN losal AND hisal);
 
- That writes plan details into a table which can be queried to yield results like this: 
- 
ID  PAR Query Plan
 
 --- --- --------------------------------------------------
 0     Select Statement   Cost = 69602
 1   0   Nested Loops
 2   1     Nested Loops
 3   2       Merge Join
 4   3         Sort Join
 5   4           Table Access Full T3
 6   3         Sort Join
 7   6           Table Access Full T4
 8   2       Index Unique Scan T2
 9   1     Table Access Full T1