Required help for a query

Question

Hi All....
Required help for one more query.
I have a table with data like this:
Cust_id Transaction_no
111 1
111 2
111 3
111 4
111 5
111 6
222 7
222 8
333 9
333 10
333 11
333 12
I wrote the following query :
select cust_id, ntile(3) over (order by cust_id) "Bucket" from trans_detls
The output is like this :
Cust_id Bucket
111 1
111 1
111 1
111 1
111 2
111 2
222 2
222 2
333 3
333 3
333 3
333 3
The problem is that I dont want the cust_id to overlap in buckets. That is one cust_id should be present in only one bucket.
Is this possible?
Thanks in advance.
Ameya

Answer 1

Or Something like..
SQL> select * from test;
        ID         NO
       111          1
       111          2
       111          3
       111          4
       111          5
       111          6
       222          7
       222          8
       333          9
       333         10
       333         11
       333         12
12 rows selected.
SQL> select id, ntile(3) over (order by rn) "Bucket"
  2  from(
  3      select id,row_number() over(partition by id order by no) rn
  4      from test);
        ID     Bucket
       111          1
       222          1
       333          1
       111          1
       222          2
       333          2
       111          2
       333          2
       111          3
       333          3
       111          3
       111          3
12 rows selected.