How to calculate daily population in DAX

问题

I'm trying to calculate the daily population of patients at our center for any given date using the patient's booking date (start date) and their release date -- using DAX and Power Pivot. I'm planning on using it in PowerBI eventually.

I've tried the formula below. I'm not getting any errors, but when I go to create a pivot table/chart in excel, I'm not getting the correct output.

I'm only using two tables: 1) a main table with the patient data and 2) a date table (calendar) and have established a relationship between the two tables.

The booking table has Patient ID, Booking Date, Release Date columns. I'd like to be able to create a graph showing the total population by day taking both dates into consideration.

DailyPop :=
CALCULATE (
    COUNTROWS ( Patients ),
    FILTER (
        Patients,
        AND (
            Patients[Booking Date] > MIN ( 'Calendar'[Date] ),
            Patients[Release Date] < MAX ( 'Calendar'[Date] )
        )
    )
)

回答1:

You can add an extra column on your date table:

PatientCount:= SUMX(Patients,IF(Patients[Booking Date]<='Calendar'[Date] && Patients[Release Date]>='Calendar'[Date],1,0))

来源：https://stackoverflow.com/questions/55961210/how-to-calculate-daily-population-in-dax