1 hierachical Queries
select [level],colun,expr......
from table
[where condition(s)]
[start with condition(s)]
[connect by prior condition(s)]
where condition
exprcompparison_operator expr
2 Starting Point
.Specifies the condition that must be met
.Accepts any valid condition
3 Waling the Tree
connect by prior column1=column2
walk from the top donw ,using the employees table
top donw
column1=parentkey
column2=childkey
bottom up
column1=child key
column2=parent key
select level,last_name
from employees
start with last_name='king'
connect by prior employee_id=manager_id;