Using CTE instead of Cursor

Question

I have the following table structure.

I just want to update SubId to all the rows where it is null and where the RawLineNumber is ascending by 1 and also the SeqNumber ascending by 1.

RawlineNumber Claimid SubId SeqNumber
1             6000    A100  1
2             6000    NULL  2
3             6000    NULL  3
10            6000    A200  1
11            6000    NULL  2
25            6000    A300  1
26            6000    NULL  2
27            6000    NULL  3

I want to update
SubId of RawLineNumber 2 and 3 with A100,
SubId of RawLineNumber 11 with A200,
SubId of RawLineNumber 26 and 27 with A300.

I have a cursor which does the job but can I have a CTE to take care of it ?

Answer 1

UPDATE  m
SET     subid = q.subid 
FROM    mytable m
CROSS APPLY
        (
        SELECT  TOP 1 subid 
        FROM    mytable mi
        WHERE   mi.rawLineNumber  < m.rawLineNumber 
                AND mi.subid IS NOT NULL
        ORDER BY
                rawLineNumber DESC
        ) q
WHERE   m.subid IS NULL