Hierarchy problem in sql query

Question

Hello Experts,
               I am using oracle 11g database with sql developer tool at windows 7.I am trying to make hierarchy for my table data.I have a table tbl_state as
State_Code
State_Name
Country_Code
1
AH
0
2
BH
91
3
CI
72
4
DI
72
5
EH
91
6
FI
72
7
GJ
83
8
HJ
83
I want hierarchy as: set all states under their country for this I have tried a query as:
SELECT 1, LEVEL, STATE_NM, null, to_char(SATE_CODE) FROM tbl_state CONNECT BY PRIOR SATE_CODE = COUNTRY_CODE start with COUNTRY_CODE=0
but there is no output as i want.Please suggest me what is going wrong here and if there is any better optimized way to make such hierarchy then please give me.
thank  you
regards
aaditya

Answer 1

Hi,
You always need to post CREATE TABLE and INSERT statements for sample data, so that the people who want to help you can re-create the problem and test their ideas.  If you post statements that don't work, you're just wasting your own and other peoples' time.  Do you wnat to get answers that work?  Then show the same courtesy to the people who try to help you.  Test (and, if necessary, correct) your statements before you post them.
None of the INSERT statements you posted work with the given CREATE TABLE statement.  You should always explicity list the columns in an INSERT statement, like this:
INSERT INTO tbl_state (sate_code, state_nm, country_code)
               VALUES (1,         'AA',     0);
If you add new columns to the table, old INSERT statements like this will still work.
Here's one way to do what you requested:
SELECT    CASE
              WHEN  GROUPING (state_nm) = 1
              THEN  country_code
          END    AS country_code
,         state_nm
FROM      tbl_state  t
GROUP BY  country_code
,         ROLLUP (state_nm)
ORDER BY  t.country_code
,         state_nm        NULLS FIRST
Output:
COUNTRY_CODE STATE_NM
           0
             AA
          72
             CI
             DI
             FI
          83
             GJ
             HJ
          91
             BH
             EH
             IH
Is the order of countries in your desired output important?  If you really need 91 between 0 and 72, explain why, and we'll find a way to code it.