SQL: group by some data

Question

Hi expert
I have a table with the column FIRST and LAST as per example
>
FIRST;LAST
FIRST1;LAST1
FIRST2;LAST2
FIRST3;LAST3
FIRST4;LAST4
FIRST5;LAST5
FIRST6;LAST6
FIRST7;LAST7
FIRST8;LAST8
FIRST9;LAST9
FIRST10;LAST10
FIRST11;LAST11
FIRST12;LAST12
>
I'd like to do an sql that create the value of column ID with a "group by" by 5 records. For example from 1 to 5 the ID will be 1, from 6 to 10 the ID will be 2. Below the result that I'd to do
>
ID;FIRST;LAST
1;FIRST1;LAST1
1;FIRST2;LAST2
1;FIRST3;LAST3
1;FIRST4;LAST4
1;FIRST5;LAST5
2;FIRST6;LAST6
2;FIRST7;LAST7
2;FIRST8;LAST8
2;FIRST9;LAST9
2;FIRST10;LAST10
;FIRST11;LAST11
;FIRST12;LAST12
>
The last 2 records will not a ID because the count of them is less of 5.
Many thanks for any idea.
Cheers,
Lain

Answer 1

Or like this...
SQL> ed
Wrote file afiedt.buf
  1  with t as (select 'FIRST1' as FIRST, 'LAST1' as LAST from dual union all
  2             select 'FIRST2', 'LAST2' from dual union all
  3             select 'FIRST3', 'LAST3' from dual union all
  4             select 'FIRST4', 'LAST4' from dual union all
  5             select 'FIRST5', 'LAST5' from dual union all
  6             select 'FIRST6', 'LAST6' from dual union all
  7             select 'FIRST7', 'LAST7' from dual union all
  8             select 'FIRST8', 'LAST8' from dual union all
  9             select 'FIRST9', 'LAST9' from dual union all
10             select 'FIRST10', 'LAST10' from dual union all
11             select 'FIRST11', 'LAST11' from dual union all
12             select 'FIRST12', 'LAST12' from dual)
13  --
14  -- End Of Test Data
15  --
16  select decode(count(*) over (partition by id), 5, id) as id
17        ,first
18        ,last
19  from (
20        select floor((row_number() over (order by ord)-1)/5)+1 as id
21              ,first
22              ,last
23              ,ord
24        from (select first, last, to_number(replace(first,'FIRST')) ord from t)
25       )
26* order by ord
SQL> /
        ID FIRST   LAST
         1 FIRST1  LAST1
         1 FIRST2  LAST2
         1 FIRST3  LAST3
         1 FIRST4  LAST4
         1 FIRST5  LAST5
         2 FIRST6  LAST6
         2 FIRST7  LAST7
         2 FIRST8  LAST8
         2 FIRST9  LAST9
         2 FIRST10 LAST10
           FIRST11 LAST11
           FIRST12 LAST12
12 rows selected.
SQL>Though, I assume your data is not "FIRST1", "FIRST2" etc., so the ordering of the data will have to be done according to what data you have. In my solution I've stripped out the word "FIRST" to allow it to be ordered on the numeric part of the data. I assume you've got some other data there to allow you to determine the order though.