Port MySQL script to MS SQL -> simultaneous data asignement and retrieval - mysql

Question

I have been trying to make this work for hours but I can't really find a way to do it. I have a MySQL script that I need to migrate to MS SQL 2014, however, I can't seem to make it work. As far as I have understood, the big issue is that MySQL allows this kind of instructions:
SELECT #row_number = #row_number + 1, hora_int FROM table1;
where you assign a value at the same time you retrieve data, but MS SQL does not.
I have a relatively big script which has that issue:
SELECT GLOBAL.year, GLOBAL.month, '1111111' as metric_id, GLOBAL.margin as metric_value FROM (SELECT A.year,
A.month,
CASE
WHEN A.month = 1 THEN (#csum_fdo := A.imp)
ELSE (#csum_fdo := #csum_fdo + A.imp) END as margin
FROM (SELECT Act.year, Act.month, Act.imp - Pas.imp as imp
FROM (SELECT year(tie.date) as year, month(tie.date) as month, sum(importe) as imp
FROM accounting con,
dim_time tie,
dim_account cta
WHERE con.account_date = tie.date
AND con.account = cta.nivel_10
AND cta.level_id = '2'
AND con.subtype_id <> 'O'
GROUP BY year(tie.date),
month(tie.date)) Act,
(SELECT year(tie.date) as year, month(tie.date) as month, sum(importe) * -1 as imp
FROM accounting con,
dim_time tie,
dim_account cta
WHERE con.account_date = tie.date
AND con.account = cta.nivel_10
AND cta.level_id = '3'
AND con.subtype_id <> 'O'
GROUP BY year(tie.date),
month(tie.date)) Pas
WHERE Act.year = Pas.year
AND Act.month = Pas.month) A,
(SELECT #csum_fdo := 0) E) GLOBAL
Can anybody point me in the direction of what I have to do to recreate the code in MS SQL? Thank you all in advance

Answer 1

In SQL Server and (MyQL 8+), you use window functions. The equivalent of:
SELECT #row_number = #row_number + 1, hora_int
FROM table1
ORDER BY col;
is:
SELECT ROW_NUMBER() OVER (ORDER BY col), hora_int
FROM table1;
If you provide sample data and desired results, it is much easier to figure out what functions you really need.

Answer 2

My big problem lied in this line:
CASE
WHEN A.month = 1 THEN (#csum_fdo := A.imp)
ELSE (#csum_fdo := #csum_fdo + A.imp) END as margin
but as Gordon Linoff pointed me. this problem could be solved with window functions, the right translation od that function is:
SUM(A.imp) OVER(PARTITION BY A.Year ORDER BY A.month) as margin
it ended up being easier than I thought
Thanks a lot and I hope it can help others as well