Power BI - 如何显示计数的平均值

Question

I have a table showing attendance of students for a town. There's a row for every student for every day they attended, so if student #1 attended 175 days over the course of the year there are 175 lines for that student, each with the unique date. Each row also contains their name, ID, the date, and what school they were at. (Elementary, Middle, High School)

I need a table that shows average count of students in attendance, by Day of week and school - so:

Columns = Day of Week (Monday-Friday)

Rows = School (Elementary, Middle, High School) So I need a matrix to show that the average attendance for the elementary school on Monday is 110, on Tuesday it's 114, etc. etc. Please help -

My formula is close - but not correct: Ave of Count of ID = AVERAGEX( KEEPFILTERS(VALUES('Attendance'[Date].[Day])), CALCULATE(COUNTA('Attendance'[ID] )))

Answer 1

Change VALUES ( Attendance[Date].[Day] ) to VALUES ( Attendance[Date] ) . This should be enough to turn your code work.

Optionally, please consider following for simplicity and better performance.

• Remove KEEPFILTERS .
• Use COUNTROWS instead of COUNTA .
• Use a calendar table instead of the date column in Attendance table.

Average Attendees Per Day = 
AVERAGEX (
    VALUES ( 'Calendar'[Date] ),
    CALCULATE ( COUNTROWS ( 'Attendance' ) )
)

Answer 2

Given you've mentioned 'Attendance'[Date].[Day] I assume you've got a single table with ID, School, Date (and a hierarchy on Date with the day name?) rather than a dimension/fact table setup.

In that case you should be able to use the following:

Avg Days=AVERAGEX(SUMMARIZE(Attendance,Attendance[ID]),CALCULATE(COUNTROWS(Attendance)))