do while loop error

[vvvvvvizard]

The script works if i manually type (@CurrentPeriod-1, -1, 0, 0, 0)

or  (@CurrentPeriod, -1, 0, 0, 0)

but not in loop

set a=0;

Do while a>-13

ODS:
Load Period,
if(len(Period)=0,'Null','Not Null') as Period_null,
IsNull(Period) as Period_nulll,
CorpCode,
RecNo() as dist,
CostCentre as CC_TESTODS,
'CC_'&CostCentre as CostCentre_ods,
'CC_'&Text(CostCentre )as CostCentre,
if(len(CostCentre)=0,'Null','Not Null') as CostCentreNull_ODS,
Trim(CombinedAccountCode) as CombinedAccountCode,
if(len(CombinedAccountCode)=0,'Null','Not Null') as Acccode_ODS,
ActLcYtd,
ActZarYtd
;
SQL DECLARE @CurrentPeriod INT
SELECT @CurrentPeriod = RP_Period
FROM FCODS.md.WorkDayCalendar
WHERE [Date] = CAST( GETDATE() AS Date )
SELECT DATEFROMPARTS(Period/ 100, Period - (Period/100)*100, 1) AS Period,
CorpCode,
CostCentre,
CombinedAccountCode,
ActLcYtd,
ActZarYtd
FROM
(
SELECT Period,
CorpCode,
CostCentre,
CombinedAccountCode,
Dimension,
SUM(ActAmtYtd) AS ActAmtYtd
FROM [xxxxxxxxxxxxxl] (@CurrentPeriod-$(a), -1, 0, 0, 0)
WHERE Dimension IN ('ActLcYtd', 'ActZarYtd')
AND Scenario = 'Act'
GROUP BY Period, CorpCode, CostCentre, CombinedAccountCode, Dimension
) p
PIVOT
(
SUM(ActAmtYtd) FOR Dimension IN ([ActLcYtd], [ActZarYtd])
) as pvt
;

Let a=a-1;

Loop

[Digvijay_Singh]

What error you are getting, don't understand what exactly the purpose of (@CurrentPeriod-1, -1, 0, 0, 0) in the script.

[vvvvvvizard]

Neither do i , but CurrentPeriod is in the format 202108 eg if i can make it a date and minus a month and make and integer again i can pass it so when 202001 comes up i get 201901 data , if you can do that even in sql