Tableau - Calculation to Display last N quarters data

Описание: Date format in the system: mm/dd/yyyy

Calculation to display Last 4 quarter data

Datetrunc('quarter',[orderdate])

returns starting date of every quarter

Jan- Mar Q1 ( 01-01-2016)
Apr-Jun Q2 ( 04-01-2016)


DATETRUNC('quarter',TODAY())

returns - current quarter starting date

jan-2019 = Q1 = starting date is 1-1-2019

Last 4 quarters data

datediff('quarter',DATETRUNC('quarter',[Order Date]),DATETRUNC('quarter',TODAY()))

return 0 for the current quarter

we need 0,1,2,3 (4 quarters)

-continous line is not possible when there is a change in the year
Making the year quarter field as continuous will not help

if we year, Q1 will be starting , in this case it should be at the last position Q1-2019

str(YEAR([Order Date]))+ " - Q" + str(DATEPART('quarter',[Order Date]))