树型数据结构SQL语句的写法

?找出所有的页节点，本例中就是找出所有的普通雇员，使用如下语句：
SELECT t2.lname, t2.salary,            (SELECT SUM(t1.salary) FROM employee t1            START WITH t1.lname = t2.lname            CONNECT BY t1.manager_emp_id = PRIOR t1.emp_id) sum_salary            FROM employee t2;
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