SQL 2000 Row numbering with GROUP BY - sql-server-2000

Question

This is my Table
################################
# id_formfield # ID # int_Sort #
################################
# 1 # 1 # 2 #
# 2 # 1 # 3 #
# 3 # 1 # 4 #
# 4 # 1 # 4 #
# 5 # 1 # 4 #
# 6 # 2 # 1 #
# 7 # 2 # 3 #
# 8 # 2 # 3 #
# 9 # 2 # 4 #
As you can see my int_sort column is messed up somehow with equal numbers and I wanna to make it sequence with row number and reset row number when ID changes.
this should be result:
############################################
# id_formfield # ID # int_Sort # rownumber #
############################################
# 1 # 1 # 2 # 1 #
# 2 # 1 # 3 # 2 #
# 3 # 1 # 4 # 3 #
# 4 # 1 # 4 # 4 #
# 5 # 1 # 4 # 5 #
# 6 # 2 # 1 # 1 #
# 7 # 2 # 3 # 2 #
# 8 # 2 # 3 # 3 #
# 9 # 2 # 4 # 4 #
Edit : id_formfield is my primary key and order by int_sort ascending

Answer 1

Following script should get you started. In a nutshell, the script
creates a temp table, adding an IDENTITY column to serve as rownumber
inserts your original data into the temp table
uses MIN(Rownumber) for each ID to get an offset.
JOIN the temp table with the calculated offsets to restart the count for each group.
SQL Statement
CREATE TABLE #TempTable (Rownumber INTEGER IDENTITY(1, 1), ID INTEGER)
SET IDENTITY_INSERT #TempTable OFF
INSERT INTO #TempTable
SELECT *
FROM YourOriginalTable
ORDER BY ID, int_Sort
SELECT t.ID, t.Rownumber, t.Rownumber - o.Offset
FROM #TempTable t
INNER JOIN (
SELECT ID, MIN(Rownumber) - 1 AS Offset
FROM #TempTable
GROUP BY ID
) o ON o.ID = t.ID
DROP TABLE #TempTable
Test script
DECLARE #YourTable TABLE (ID VARCHAR(1))
CREATE TABLE #TempTable (Rownumber INTEGER IDENTITY(1, 1), ID INTEGER)
SET IDENTITY_INSERT #TempTable OFF
INSERT INTO #YourTable (ID) VALUES (1)
INSERT INTO #YourTable (ID) VALUES (1)
INSERT INTO #YourTable (ID) VALUES (1)
INSERT INTO #YourTable (ID) VALUES (1)
INSERT INTO #YourTable (ID) VALUES (1)
INSERT INTO #YourTable (ID) VALUES (2)
INSERT INTO #YourTable (ID) VALUES (2)
INSERT INTO #YourTable (ID) VALUES (2)
INSERT INTO #YourTable (ID) VALUES (2)
INSERT INTO #TempTable
SELECT *
FROM #YourTable
ORDER BY ID
SELECT t.ID, t.Rownumber, t.Rownumber - o.Offset
FROM #TempTable t
INNER JOIN (
SELECT ID, MIN(Rownumber) - 1 AS Offset
FROM #TempTable
GROUP BY ID
) o ON o.ID = t.ID
DROP TABLE #TempTable

Answer 2

I assume you have a primary key in your table that is called PK and that you want to update the column int_sort.
select cast(PK as int) as PK,
ID,
identity(int, 1, 1) as rownumber
into #T
from YourTable
order by ID, int_sort
update YourTable
set int_sort = T.rownumber - T2.rownumber + 1
from #T as T
inner join (
select ID, min(rownumber) as rownumber
from #T
group by ID
) as T2
on T.ID = T2.ID
where T.PK = YourTable.PK
drop table #T

Answer 3

I have assumed that your Primary Key column is named idpk. You can obtain the desired row numbers using the following query:
SELECT ts.id, ts.int_sort,
(SELECT count(*) FROM tosort
WHERE id = ts.id AND int_sort <= ts.int_sort
AND idpk <= ts.idpk) AS row_number
FROM tosort AS ts
ORDER BY ts.id, ts.int_sort, ts.idpk;
I have created a sample case on SQL Fiddle, though only 2008 R2 is available there.
I hope this will work on SQL Server 2000.