WINDOW

Applies to: Calculated column Calculated table Measure Visual calculation

Returns multiple rows which are positioned within the given interval.

Syntax

WINDOW ( from[, from_type], to[, to_type][, <relation> or <axis>][, <orderBy>][, <blanks>][, <partitionBy>][, <matchBy>][, <reset>] )

Parameters

Return value

All rows from the window.

Remarks

Except for columns added by DAX table functions, each column in <relation>, when <matchBy> is not present, or each column in <matchBy> and <partitionBy>, when <matchBy> is present, must have a corresponding outer value to help define the current row on which to operate. If <from_type> and <to_type> both have value ABS, then the following applies only to the <partitionBy> columns:

• If there is exactly one corresponding outer column, its value is used.
• If there is no corresponding outer column:
  • WINDOW will first determine all columns that have no corresponding outer column.
  • For every combination of existing values for these columns in WINDOW’s parent context, WINDOW is evaluated, and the corresponding rows is returned.
  • WINDOW final output is a union of these rows.
• If there is more than one corresponding outer column, an error is returned.

If all of <relation>'s columns were added by DAX table functions, an error is returned.

If <matchBy> is present, WINDOW will try to use <matchBy> and <partitionBy> columns to identify the row.
If <matchBy> is not present and the columns specified within <orderBy> and <partitionBy> cannot uniquely identify every row in <relation>, then:

• WINDOW will try to find the least number of additional columns required to uniquely identify every row.
• If such columns can be found, WINDOW will automatically append these new columns to <orderBy>, and each partition is sorted using this new set of orderBy columns.
• If such columns cannot be found, an error is returned.

An empty table is returned if:

• The corresponding outer value of an <orderBy> or <partitionBy> column does not exist within <relation>.
• The whole window is outside the partition, or the beginning of the window is after its ending.

If WINDOW is used within a calculated column defined on the same table as <relation>, and <orderBy> is omitted, an error is returned.

If the beginning of the window turns out be before the first row, then it’s set to the first row. Similarly, if the end of the window is after the last row of the partition, then it's set to the last row.

<reset> can be used in visual calculations only, and cannot be used in combination with <orderBy> or <partitionBy>. If <reset> is present, <axis> can be specified but <relation> cannot.

Example 1 - measure

The following measure:

3-day Average Price = 
AVERAGEX(
    WINDOW(
        -2,REL,0,REL,
        SUMMARIZE(ALLSELECTED('Sales'), 'Date'[Date], 'Product'[Product]),
        ORDERBY('Date'[Date]),
        KEEP,
        PARTITIONBY('Product'[Product])
    ), 
    CALCULATE(AVERAGE(Sales[Unit Price]))
)

Returns the 3-day average of unit prices for each product. Note the 3-day window consists of three days in which the product has sales, not necessarily three consecutive calendar days.

Example 2 - measure

The following measure:

RunningSum =
SUMX (
    WINDOW (
        1, ABS, 0, REL,
        ALLSELECTED (
            'Date'[Fiscal Year],
            'Date'[Month Number Of Year]
        ),
        PARTITIONBY ( 'Date'[Fiscal Year] )
    ),
    [Total Sales]
)

Returns the running sum for Total Sales by Month Number Of Year, restarting for every Fiscal Year:

Example 3 - visual calculation

The following visual calculation DAX query:

TotalSalesRunningSumByYear = SUMX(WINDOW(0, ABS, 0, REL, ROWS, HIGHESTPARENT), [SalesAmount])

Returns the cumulative total sales by month, calculated along each year. The values 1 and -2 could be used instead of HIGHESTPARENT, with the same results.

The screenshot below shows the visual matrix and the visual calculation expression:

Example 4 - visual calculation

The following visual calculation DAX query:

TotalSalesRunningSumByQuarter = SUMX(WINDOW(0, ABS, 0, REL, , -1), [SalesAmount])

Returns the cumulative total sales by month, calculated along each quarter.

Related content

INDEX
MOVINGAVERAGE
OFFSET
ORDERBY
PARTITIONBY
RANGE
RANK
ROWNUMBER RUNNINGSUM