How to calculate number of customer who has continuous 3 months sales

[GraceGao]

Hi Experts,

How to calculate number of customers who has continuous 3 months sales like in below table? Thanks.

eg. assume now is 202012, expected result is 1, customer A.

Year months   customer A, customer B

202012              100,                  100

202011               100,                 0

202010               100,                 0

[Taoufiq_Zarra]

@GraceGao  one solution is to use

for this example : first Crosstable

CrossTable(customer, Sales)

LOAD * INLINE [
Year months,customer A,customer B, customer C 
202012,100,100,10
202011,50,0,20
202101,60,0,30
];

this function :

=count({<customer={"=sum({<[Year months]={[$(=Date(today(),'YYYYMM'))]}>} Sales)<>0 and sum({<[Year months]={[$(=Date(addmonths(today(),-1),'YYYYMM'))]}>} Sales)<>0 and sum({<[Year months]={[$(=Date(addmonths(today(),-2),'YYYYMM'))]}>} Sales)<>0"}>}distinct customer)

output:

[GraceGao]

Thanks Zarra