Adding up data from 2 source: the total cannot be <0

[Kingazawora]

Hello

I have two data sources per customer:

1) sales data, where total per customer per month is positive

Customer	Total sales per month
A	200
B	300
C	100

2) sales data, where I have sales line items per customer, where data has negative value

Customer	Sales line items
A	-250
B	-100
C	-90
C	-50

The rule is: I can add line items to the data no 1 only if the value of added itels is higher than 0 per customer. 

So for:

Customer A, I cannot add data from source 2 as the total will be lower than 0

Customer B, I cann add data as total will not be less than 0

Customer C, I can add only the first line item as this will be making the total >0

Is there any way to have thnis logic implemented?

[sparksun]

What's the meaning of "add line items to the data"? Could you show your expected output?

[JamesCharnley · Accepted solution]

Hi @Kingazawora 

As said above it's not too clear what you'd like but I've taken a stab that involves joining first and filtering out rows based on your condition afterwards, using the multi-row to evaluate rows one at a time when there are multiple.

[Kingazawora]

When the total for the month (sales data 1) per customer is positive, I can add data from sales from the table 2 but only those that I add and the total of 1 sth table will not be >0.

[Kingazawora]

Thanks! I have slightly amended.