How to Display parent Child in specific order by using sql query

Suppose,I have table in which i have two columns one is parent id a开发者_开发知识库nd onother is child id and child can be parent of another child and so on.......something like this

Parent id      Child id  
p1             c1  
c1             c2  
p1             c3  
c1             c4  
p3             c5  
p3             c6 
c4             c7 
c5             c8

i am trying to write a query which gives me output like this.......

  
Parent id      Child id 
p1             c1    
p1             c3  
c1             c2  
c1             c4 
c4             c7
p3             c5
p3             c6
c5             c8
c8 ..................and so on.....

Guys please help me out... Thanks in advance....

If I understand it correctly, you need parents before children and children ordered within each parent ( are you building some kind of tree structure in you application?)

Simple

SELECT *
FROM Table
ORDER BY ParentID, ChildID

should do the trick.