OFFSET DAX Function (Filter)
Retrieves a single row from a relation by moving a number of rows within the specified partition, sorted by the specified order or on the axis specified.
Syntax
Parameter | Attributes | Description |
---|---|---|
Delta |
The number of rows before (negative value) or after (positive value) the current row from which to obtain the data. It can be any DAX expression that returns a scalar value. |
|
Relation Iterator |
Optional |
A table expression from which the output row is returned.
|
OrderBy Row Context |
Optional |
An ORDERBY() clause containing the columns that define how each partition is sorted.
|
Blanks | Optional |
An enumeration that defines how to handle blank values when sorting. |
PartitionBy | Optional |
A PARTITIONBY() clause containing the columns that define how Relation is partitioned. |
MatchBy | Optional |
Columns that define how the current row is identified. |
Reset | Optional |
Specifies how the calculation restarts. Valid values are: None, LowestParent, HighestParent, or an integer. |
Return values
One or more rows from Relation.
Remarks
Each OrderBy and PartitionBy column must have a corresponding outer value to help define the current row on which to operate, with the following behavior:
- If there is exactly one corresponding outer column, its value is used.
- If there is no corresponding outer column, then:
- OFFSET will first determine all OrderBy and PartitionBy columns that have no corresponding outer column.
- For every combination of existing values for these columns in OFFSET’s parent context, OFFSET is evaluated and a row is returned.
- OFFSET’s final output is a union of these rows.
- If there is more than one corresponding outer column, an error is returned.
If the non-volatile columns specified within OrderBy and PartitionBy can’t uniquely identify every row in Relation, then:
- OFFSET will try to find the least number of additional columns required to uniquely identify every row.
- If such columns can be found, OFFSET 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 Delta value causes a shift to a row that does not exist within the partition.
If OFFSET is used within a calculated column defined on the same table as Relation, and OrderBy is omitted, an error is returned.
» 4 related functions
Examples
DEFINE MEASURE Sales[Prev Year Sales] = CALCULATE ( [Sales Amount], OFFSET ( -1, ALLSELECTED ( 'Date'[Year] ), ORDERBY ( 'Date'[Year], ASC ) ) ) EVALUATE SUMMARIZECOLUMNS ( 'Date'[Year], TREATAS ( { 2019, 2020 }, 'Date'[Year] ), "Sales Amount", [Sales Amount], "Prev Year Sales", [Prev Year Sales] )
Date[Year] | Sales Amount | Prev Year Sales |
---|---|---|
2,019 | 3,550,194.76 | (Blank) |
2,020 | 769,835.80 | 3,550,194.76 |
DEFINE TABLE ProcessData = -- Create a table with index column and "process" values from the DAX Guide db SELECTCOLUMNS ( SUMMARIZECOLUMNS ( 'Date'[Calendar Year Month Number], FILTER ( ALL ( 'Date'[Calendar Year Month Number] ), 'Date'[Calendar Year Month Number] < 200804 ), "Amt", [Sales Amount] ), "Index", [Calendar Year Month Number], "Value", [Amt] ) -- Basic sum measure of the value column MEASURE ProcessData[SumValue] = SUM ( ProcessData[Value] ) -- Average value of the data VAR MeanValue = AVERAGE ( ProcessData[Value] ) -- Use the OFFSET function to first calculate the absolute differences -- between two consequent values (a.k.a. Moving Range) -- https://en.wikipedia.org/wiki/Shewhart_individuals_control_chart MEASURE ProcessData[MovingRange] = VAR PreviousValue = CALCULATE ( [SumValue], OFFSET ( -1, ORDERBY ( ProcessData[Index] ) ) ) RETURN IF ( NOT ISBLANK ( PreviousValue ), ABS ( [SumValue] - PreviousValue ) ) -- Derive process standard deviation or "sigma" based on the Moving Range VAR Sigma = VAR MeanMovingRange = CALCULATE ( AVERAGEX ( ALL ( ProcessData[Index] ), [MovingRange] ) ) RETURN MeanMovingRange * SQRTPI ( 1 ) / 2 -- Use the WINDOW function to implement the WE Rule 2 for process instability detection: -- "Two out of three consecutive points fall beyond the 2σ-limit (in zone A or beyond), -- on the same side of the centerline" -- https://en.wikipedia.org/wiki/Western_Electric_rules MEASURE ProcessData[Rule2Test] = VAR ZoneARowsPositive = CALCULATE ( COUNTROWS ( ProcessData ), FILTER ( WINDOW ( -2, 0, ORDERBY ( ProcessData[Index] ) ), [SumValue] >= MeanValue + 2 * Sigma ) ) VAR ZoneARowsNegative = CALCULATE ( COUNTROWS ( ProcessData ), FILTER ( WINDOW ( -2, 0, ORDERBY ( ProcessData[Index] ) ), [SumValue] <= MeanValue - 2 * Sigma ) ) RETURN -- Flag the rows where the rule is violated IF ( ZoneARowsPositive >= 2 || ZoneARowsNegative >= 2, 1 ) EVALUATE SUMMARIZECOLUMNS ( ProcessData[Index], "SumValue", [SumValue], "Process Mean", MeanValue, "-2 σ", MeanValue - 2 * Sigma, "+2 σ", MeanValue + 2 * Sigma, "Rule 2 Indicator", [Rule2Test] )
Index | SumValue | Process Mean | -2 σ | +2 σ | Rule 2 Indicator |
---|---|---|---|---|---|
200,701 | 794,248.24 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,702 | 891,135.91 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,703 | 961,289.24 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,704 | 1,128,104.82 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,705 | 936,192.74 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,706 | 982,304.46 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,707 | 922,542.98 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,708 | 952,834.59 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,709 | 1,009,868.98 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,710 | 914,273.54 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,711 | 825,601.87 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,712 | 991,548.75 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,801 | 656,766.69 | 875,088.76 | 685,032.06 | 1,065,145.45 | (Blank) |
200,802 | 600,080.00 | 875,088.76 | 685,032.06 | 1,065,145.45 | 1 |
200,803 | 559,538.52 | 875,088.76 | 685,032.06 | 1,065,145.45 | 1 |
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Last update: Nov 7, 2024 » Contribute » Show contributors
Contributors: Alberto Ferrari, Marco Russo, Ville-Pietari Louhiala
Microsoft documentation: https://learn.microsoft.com/en-us/dax/offset-function-dax