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DEFINE

Introduces a statement with one or more entity definitions that can be applied to one or more EVALUATE statements of a DAX query.

Syntax

[DEFINE 
    (
     (COLUMN <table name>[<column name>] = <scalar expression>) |
     (FUNCTION <function name> = ([parameter name]: [parameter type], ...) => <function body>) |
     (MEASURE <table name>[<measure name>] = <scalar expression>) | 
     (TABLE <table name> = <virtual table definition>) | 
     (VAR <var name> = <table or scalar expression>) |
    ) + 
]

(EVALUATE <table expression>) +

Parameters

Term Definition
Entity COLUMN1, FUNCTION, MEASURE, TABLE1, or VAR.
name The name of a column, function, measure, table, or var definition. It cannot be an expression. The name does not have to be unique. The name exists only for the duration of the query.
expression Any DAX expression that returns a table or scalar value. The expression can use any of the defined entities. If there is a need to convert a scalar expression into a table expression, wrap the expression inside a table constructor with curly braces {}, or use the ROW() function to return a single row table.
parameter type, parameter name, function body See FUNCTION statement.

[1] Caution: Query scoped TABLE and COLUMN definitions are meant for internal use only. While you can define TABLE and COLUMN expressions for a query without syntax error, they may produce runtime errors and are not recommended.

Remarks

  • A DAX query can have multiple EVALUATE statements, but can have only one DEFINE statement. Definitions in the DEFINE statement can apply to any EVALUATE statements in the query.

  • At least one definition is required in a DEFINE statement.

  • Measure definitions for a query override model measures of the same name.

  • VAR names have unique restrictions. To learn more, see VAR - Parameters.

  • To learn more about how a DEFINE statement is used, see DAX queries.

  • To learn more about virtual column, see Virtual Column

  • To learn more about virtual table, see Virtual Table

  • To learn more about DAX user defined functions, see DAX User Defined Functions

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