INDEX DAX Function (Filter)

Retrieves a row at an absolute position (specified by the position parameter) within the specified partition sorted by the specified order or on the axis specified.

Syntax

INDEX ( <Position> [, <Relation>] [, <OrderBy>] [, <Blanks>] [, <PartitionBy>] )
Parameter Attributes Description
Position

The absolute position (1-based) from which to obtain the data:

  • Position is positive: 1 is the first row, 2 is the second row, etc.
  • Position is negative: -1 is the last row, -2 is the second last row, etc.

When Position is out of the boundary, or zero, or BLANK(), INDEX will return an empty table. It can be any DAX expression that returns a scalar value.

Relation Optional

A table expression from which the output is returned.
If specified, all columns in OrderBy and PartitionBy must come from it.
If omitted:

  • OrderBy must be explicitly specified.
  • All OrderBy and PartitionBy columns must come from a single table.
  • Defaults to ALLSELECTED() of all columns in OrderBy and PartitionBy.
OrderBy Optional

An ORDERBY() clause containing the columns that define how each partition is sorted.
If omitted:

  • Relation must be explicitly specified.
  • Defaults to ordering by every column in Relation.
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 KEEP (default), where the behavior for numerical/date 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.

Return values

Table An entire table or a table with one or more columns.

A row at an absolute position.

Remarks

Each PartitionBy column must have a corresponding outer value to help define the “current partition” 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:
    • INDEX will first determine all PartitionBy columns that have no corresponding outer column.
    • For every combination of existing values for these columns in INDEX’s parent context, INDEX is evaluated and a row is returned.
    • INDEX’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 cannot uniquely identify every row in Relation:

  • INDEX will try to find the least number of additional columns required to uniquely identify every row.
  • If such columns can be found, INDEX 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 a PartitionBy column does not exist within Relation.
  • The Position value refers to a position that does not exist within the partition.

If INDEX is used within a calculated column defined on the same table as Relation and OrderBy is omitted, an error is returned.

Related functions

Other related functions are:

Last update: Jan 31, 2023   » Contribute   » Show contributors

Contributors: Alberto Ferrari, Marco Russo, Daniil Maslyuk

Microsoft documentation: https://learn.microsoft.com/en-us/dax/index-function-dax

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Context Transition

This function performs a Context Transition if called in a Row Context. Click to read more.

Row Context

This expression is executed in a Row Context. Click to read more.

Iterator

Not recommended

The use of this function is not recommended. See Remarks and Related functions for alternatives.

Not recommended

The use of this parameter is not recommended.

Deprecated

This function is deprecated. Jump to the Alternatives section to see the function to use.

Volatile

A volatile function may return a different result every time you call it, even if you provide the same arguments. Click to read more.

Deprecated

This parameter is deprecated and its use is not recommended.

DirectQuery compatibility

Limitations are placed on DAX expressions allowed in measures and calculated columns.
The state below shows the DirectQuery compatibility of the DAX function.

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