Set analysis

[risabhroy_03]

I want to achieve this using set analysis in qlik sense

I want to sum my Quantity

If [Table Source] = 'WHUIL200' then [INDT] = [GMT]

where INDT and GMT are two date fields and [GMT] = last month end date.

[Anil_Babu_Samineni]

For me this is similar to this

Set Analysis - Qlik Community - 1854127

Perhaps this?

Sum({<[Table Source]={'WHUIL200'}, INDT={"=INDT=GMT"}>} Quantity)

[risabhroy_03]

I am using this

if([Table Source]='WHUIL200',Sum({$<[Invoice_Date_GMT]={"$(vLastmonthdate)"}>} Quantity))

I want to sum my quantity when my [Invoice_Date_GMT] = my variable vLastmonthdate but it shows 0.

Please help