Connect By with composite Key

Question

Hello
I have a table more or less like this
ID - CONTINENT- COUNTRY-CITY
1 ASIA
2 ASIA CHINA
3 ASIA CHINA BEIJING
4 ASIA CHINA XANGAI
5 ASIA JAPAN
6 ASIA JAPAN TOKIO
7 EUROPE
8 EUROPE GERMANY
Altough I have a sequencial primary key, that key os not used to relate to the "master record". The only way I have to know which record depends on which is by using a composite key (in the real table those three columns are numbers, and their combination is unique).
Is there a way to use an hierarquical query on this table?
Thanks for any help

Answer 1

Nuno wrote:
example:
CREATE TABLE PLACES
(ID, CONTINENT,COUNTRY,CITY,NAME)Does that command work when you run it? I get 'ORA-02263: need to specifuy the datatype for this column".
INSERT INTO PLACES (1,1,NULL,NULL,'ASIA')
INSERT INTO PLACES (2,1,1,NULL,'CHINA')
INSERT INTO PLACES (3,1,1,1,'BEIJING')
INSERT INTO PLACES (4,1,1,2,'XANGAI)
INSERT INTO PLACES (5,1,2,NULL,'JAPAN')
INSERT INTO PLACES (6,1,2,1,'TOKIO')
INSERT INTO PLACES (7,2,NULL,NULL,'EUROPE')
INSERT INTO PLACES (8,2,1,NULL,'GERMANY')Do those statements work for you? I get "ORA-00928: missing SELECT keyword".
Oracle 10g is the version used...
what I want is a list like this:
ASIA
CHINA
BEIJING
XANGAI
JAPAN
TOKIO
EUROPE
GERMANY
The way I used was to create a "dummy" ID and Mother ID using both case and concatenating CONTINENT,COUNTRY,CITY fields.
Don't know if there is other cleaner way...
CONTINENT || COUNTRY || CITYdummy_id,
          CASE
          WHEN COUNTRY IS NULL AND CITY IS NULL
          THEN NULL
          WHEN COUNTRY IS NOT NULL AND CITY IS NULL
          THEN CNUT1
          WHEN COUNTRY IS NOT NULL AND CITY IS NOT NULL
          THEN      CONTINENT || COUNTRY      
          END DUMMY_MOMUsing COALESCE, like Odie did, is a lot simpler.
Instead of generating a "dummy" parent_id, you may want to add a real parent_id column to the table. Then it sould be easier to do CONNECT BY queries when you needed to.
However, you can get the output you requested without anything hierarchical:
{code}
SELECT     name
FROM places
{code}
If the output somehow had to reflect the hierarchical structure then you'd have to do somehting different.
For example, to be sure children were displayed after their parents), add an ORDER BY clause:
{code}
SELECT     name
FROM places
ORDER BY continent
,      country     NULLS FIRST
,     city          NULLS FIRST
{code}
If your output need to be indented, post exactly what you want, with an explanation.
When posting any fomatted text on this site, type these 6 characters:
\{code}
(small letters only, inside curly brackets) before and after sections of formatted text, to preserve spacing.
Perhaps you want something like this:
{code}
SELECT     NVL2 (country, ' ', NULL)     ||
     NVL2 (city,     ' ', NULL)     ||
     name                         AS indented_name
FROM places
ORDER BY continent
,      country     NULLS FIRST
,     city          NULLS FIRST
{code}
You can always do a CONNECT BY query, as Odie demonstrated.