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WINDOW

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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

Term Definition
from Indicates where the window starts. It can be any DAX expression that returns a scalar value.
The behavior depends on the from_type parameter:
- If from_type is REL, the number of rows to go back (negative value) or forward (positive value) from the current row to get the first row in the window.
- If from_type is ABS, and from is positive, then it’s the position of the start of the window from beginning of the partition. Indexing is 1-based. For example, 1 means window starts from the beginning of the partition. If from is negative, then it’s the position of the start of the window from the end of the partition. -1 means the last row in the partition.
from_type Modifies behavior of the from parameter. Possible values are ABS (absolute) and REL (relative). Default is REL.
to Same as from, but indicates the end of the window. The last row is included in the window.
to_type Same as from_type, but modifies the behavior of to.
relation (Optional) A table expression from which the output rows are returned.
If specified, all columns in partitionBy must come from it or a related table.
If omitted:
- orderBy must be explicitly specified.
- All orderBy and partitionBy expressions must be fully qualified column names and come from a single table.
- Defaults to ALLSELECTED() of all columns in orderBy and partitionBy.
axis (Optional) An axis in the visual shape. Available in visual calculations only, and replaces relation.
orderBy (Optional) An ORDERBY() clause containing the expressions that define how each partition is sorted.
If omitted:
- relation must be explicitly specified.
- Defaults to ordering by every column in relation that is not already specified in partitionBy.
blanks (Optional) An enumeration that defines how to handle blank values when sorting.
This parameter is reserved for future use.
Currently, the only supported value is DEFAULT, where the behavior for numerical values is blank values are ordered between zero and negative values. The behavior for strings is blank values are ordered before all strings, including empty strings.
partitionBy (Optional) A PARTITIONBY() clause containing the columns that define how relation is partitioned. If omitted, relation is treated as a single partition.
matchBy (Optional) A MATCHBY() clause containing the columns that define how to match data and identify the current row.
reset (Optional) Available in visual calculations only. Indicates if the calculation resets, and at which level of the visual shape's column hierarchy. Accepted values are: NONE, LOWESTPARENT, HIGHESTPARENT, or an integer. The behavior depends on the integer sign:
- If zero or omitted, the calculation does not reset. Equivalent to NONE.
- If positive, the integer identifies the column starting from the highest, independent of grain. HIGHESTPARENT is equivalent to 1.
- If negative, the integer identifies the column starting from the lowest, relative to the current grain. LOWESTPARENT is equivalent to -1.

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:

Year Month Number Of Year Sales Amount RunningSum
FY2018 1 $1,327,675 $1,327,675
FY2018 2 $3,936,463 $5,264,138
FY2018 3 $700,873 $5,965,011
FY2018 4 $1,519,275 $7,484,286
FY2018 5 $2,960,378 $10,444,664
FY2018 6 $1,487,671 $11,932,336
FY2018 7 $1,423,357 $13,355,693
FY2018 8 $2,057,902 $15,413,595
FY2018 9 $2,523,948 $17,937,543
FY2018 10 $561,681 $18,499,224
FY2018 11 $4,764,920 $23,264,145
FY2018 12 $596,747 $23,860,891
FY2019 1 $1,847,692 $1,847,692
FY2019 2 $2,829,362 $4,677,054
FY2019 3 $2,092,434 $6,769,488
FY2019 4 $2,405,971 $9,175,459
FY2019 5 $3,459,444 $12,634,903
FY2019 6 $2,850,649 $15,485,552
FY2019 7 $2,939,691 $18,425,243
FY2019 8 $3,964,801 $22,390,045
FY2019 9 $3,287,606 $25,677,650
FY2019 10 $2,157,287 $27,834,938
FY2019 11 $3,611,092 $31,446,030
FY2019 12 $2,624,078 $34,070,109
FY2020 1 $3,235,187 $3,235,187
FY2020 2 $4,070,046 $7,305,233
FY2020 3 $4,429,833 $11,735,066
FY2020 4 $4,002,614 $15,737,680
FY2020 5 $5,265,797 $21,003,477
FY2020 6 $3,465,241 $24,468,717
FY2020 7 $3,513,064 $27,981,781
FY2020 8 $5,247,165 $33,228,947
FY2020 9 $5,104,088 $38,333,035
FY2020 10 $3,542,150 $41,875,184
FY2020 11 $5,151,897 $47,027,081
FY2020 12 $4,851,194 $51,878,275

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:

DAX visual calculation

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