Question

I have a following example – table with name, department and country. I need to create a select statement that lists all records and assigns unique number to each group of department and country (column Group in the example):

Name   Department   Country   Group
====== ============ ========= =====
James  HR           UK        1
John   HR           UK        1
Alice  Finance      UK        2
Bob    Finance      DE        3
Frank  Finance      DE        3

I thought of some select with analytic function but I found only row_number() over (partition by department, country) which numbers records inside the group and not groups themselves. Do you have any idea how to solve this problem? Thank you!

Answer 1

SELECT  t.*, q.grp
FROM    (
        SELECT  q.*, rownum AS grp
        FROM    (
                SELECT  DISTINCT department, country
                FROM    mytable
                ORDER BY
                        department, country
                ) q
        ) q
JOIN    mytable t
ON      t.department = q.department
        AND t.country = q.country 

or

SELECT  t.*, DENSE_RANK() OVER (ORDER BY department desc, country desc) AS grp
FROM    mytable