View the Exhibit and examine the details of the EMPLOYEES table.
Evaluate the following SQL statements:
Statement 1:
SELECT employee_id, last_name, job_id, manager_id
FROM employees
START WITH employee_id = 101
CONNECT BY PRIOR employee_id = manager_id AND manager_id != 108 ;
Statement 2:
SELECT employee_id, last_name, job_id, manager_id
FROM employees
WHERE manager_id != 108
START WITH employee_id = 101
CONNECT BY PRIOR employee_id = manager_id;
Which two statements are true regarding the above SQL statements? (Choose two.)
A. Statement 2 would not execute because the WHERE clause condition is not allowed in a statement that
has the START WITH clause.
B. The output for statement 1 would display the employee with MANAGER_ID 108 and all the employees
below him or her in the hierarchy.
C. The output of statement 1 would neither display the employee with MANAGER_ID 108 nor any
employee below him or her in the hierarchy.
D. The output for statement 2 would not display the employee with MANAGER_ID 108 but it would display
all the employees below him or her in the hierarchy.
Answer: CD
SQL> select lpad(ename,length(ename)+level,'*') A from emp start with ename='JONES' connect by prior
empno=mgr;
A
--------------------
*JONES
**SCOTT
***ADAMS
**FORD
***SMITH
SQL> select lpad(ename,length(ename)+level,'*') A from emp start with ename='JONES' connect by prior
empno=mgr and mgr!=7566 ;
A
--------------------
*JONES
SQL> select lpad(ename,length(ename)+level,'*') A from emp where mgr!=7566 start with ename='JONES'
connect by prior empno=mgr ;
A
--------------------
*JONES
***ADAMS
***SMITH
由此可见connect 中mgr！=7566是剪分支，而where中的 mgr！=7566是剪节点