How to Simulate ROW_NUMBER() OVER (PARTITION BY) in MS Access?

Achieving ROW_NUMBER / PARTITION BY in MS Access

In MS Access, you can emulate the functionality of the ROW_NUMBER OVER (PARTITION BY) function using an unequal self-join and aggregation.

Consider the example data:

Ino	TYPE	DOC
1	1800xxc1	3a
2	1810xxc2	3b
3	1700xxc3	3c
4	1700xxc4	3a
5	1800xxc5	3a
6	1800xxc6	3a
7	1800xxc7	3b

To achieve a similar result to ROW_NUMBER OVER (PARTITION BY DOC), execute the following query:

SELECT
    t1.DOC,
    t1.TYPE,
    COUNT(*) AS [Ino Seq]
FROM
    MyData AS t1
    INNER JOIN
    MyData AS t2
        ON t2.DOC = t1.DOC
            AND t2.Ino <= t1.Ino
GROUP BY
    t1.DOC,
    t1.TYPE
ORDER BY
    1, 3

This query will return the Ino Seq column, which assigns sequential integers to each row within the partition (DOC in this case).

In this specific case, the result will be:

DOC	TYPE	Ino Seq
3a	1800xxc1	1
3a	1700xxc4	2
3a	1800xxc5	3
3a	1800xxc6	4
3b	1810xxc2	1
3b	1800xxc7	2
3c	1700xxc3	1

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