SQL SELECT Query with returning hierarchical data - sql-server

Question

I have got a table which goes something like this:
State_id | County_id| City_id | Name | Additional_Name
-----------------------------------------------------------------
1 | 0 | 0 | California | State
1 | 1 | 0 | Los Angeles | County
1 | 1 | 1 | Los Angeles | City
1 | 2 | 0 | San Diego | County
1 | 2 | 1 | San Diego | City
2 | 0 | 0 | Texas | State
2 | 1 | 0 | Harris | County
2 | 1 | 1 | Houston | City
It goes on for 10,000 rows. What I'm trying to accomplish is to build a SELECT statement which will result in:
State | County | City
-------------------------------------------
California | Los Angeles | Los Angeles
California | San Diego | San Diego
Texas | Harris | Houston
As you can see i want to select every city and display it's state, and county. The state_id, county_id, city_id and Additonal_Name columns should be essential in solving this problem, but i have no idea how to use them.

Answer 1

This will get your data, using your current table structure:
SELECT t2.[Name] AS [State]
,t3.[Name] AS County
,t1.[Name] AS City
FROM MyTable t1
JOIN MyTable t2 -- get state
ON t2.State_id = t1.State_id
AND t2.County_id = 0
AND t2.City_id = 0
JOIN MyTable t3 -- get county
ON t3.County_id = t1.County_id
AND t3.State_id = t1.State_id
AND t3.City_id = 0
WHERE t1.City_id > 0 --(or use t1.Additional_Name = 'City'
But Really:
You should be normalizing your database into three separate tables:
City
State
County
This will make using your data, and writing queries - muchh simpler and readable.
The tables would look something like this:
State
ID Name
1 California
2 Texas
County
ID Name
1 Los Angeles
2 San Diego
3 Harris
City
ID StateID CountyID Name
1 1 1 Los Angeles
2 1 2 San Diego
3 2 3 Houston
Hopefully you can see how much easier that is to manage things. You can choose to add a StateID to the County table to normalize further. But I'll keep my answer short.
Select the same data from these new tables with a similar query:
SELECT state.[Name] AS [State]
,county.[Name] AS County
,city.[Name] AS City
FROM MyCity city
JOIN MyState state ON state.ID = city.StateID -- get state
JOIN MyCounty county ON county.ID = city.CountyID -- get county