How to count the data with certain conditions. (Count One column that has same value as another column)

[Qlik496]

Help!!!

Hello I am new to Qlik. 

I want to count all transactions which happened previous month with each customer. 

For example, when I see the transaction data that happened at 2023-08 , I want one additional column to show how many transactions we had in 2023-07 with this customer. 

So I made one column to show the current transaction month :

NUM(Month(Date#([REG_DATE],'YYYY-MM-DD')))

and then I made another column that show previous month using: 

if(NUM(Month(Date#([REG_DATE], 'YYYY-MM-DD')))=1,12,NUM(Month(Date#([REG_DATE], 'YYYY-MM-DD')))-1)

Now I want to aggregate the transaction data that occurred previous month.

So I am trying to use code like this: Column(5) is the column of previous month. 

Aggr(count(distinct if({<[NUM(Month(Date#([REG_DATE]],'YYYY-MM-DD')))]=Column(5)>},TRANSACTIONID)),CUSTOMER)

This does not work at all.

And I have no clue how I should fix this code.

Please help me.

I am not using script. I am using the sheet. 

I don't want to go deep into the script. 

[G3S]

could you share why a square bracket is being used?

Aggr(count(distinct if({<[NUM(Month(Date#([REG_DATE]],'YYYY-MM-DD')))]=Column(5)>},TRANSACTIONID)),CUSTOMER)

also the requirement for the if statement

[Qlik496]

No reason I just used it... I am newbie I just am trying in various ways...

[G3S]

from what I know, that is for fields. could you share example data (please remove any sensitive info) and a mockup of  your desired output?

 would suggest to calculate the month of REG_Date and the month prior of REG_DATE in the script  and use that calculated field in the front. 

have a look at: https://help.qlik.com/en-US/cloud-services/Subsystems/Hub/Content/Sense_Hub/ChartFunctions/SetAnalys...

[Qlik496]

Hello Thank you for the answer but  I changed my strategy to get the data. 

I think I can  count transaction happened in past 30days.

Now I am trying to use this code: 

Aggr(count(distinct if( Date(REG_DATE)-30 <= REG_DATE <=Date(REG_DATE)),TRANSID),CUSTOMER) 

Which does not work it comes with blank. 

I would try to provide mock data if you prefer.