Data Types & Variables in DAX

Data Types & Variables in DAX

  June 19, 2023    asghars

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Data Types

• DAX is strongly typed language. 
• DAX data types can be categorized into three groups: 
• Numeric
• Numeric data types include 
• Decimal
• Fixed decimal/currency
• Integer/whole numbers, 
• Percentage (same is decimal data type but with formatting as percentage)  
• Date/Time (underneath Date/Time value is stored as a Decimal Number)
• Date (same as  Date/Time value with zero decimal numbers)
• Time (same as Date/Time value with no digits to the left of the decimal place) 
• True/False
• Non-numeric
• Non-numeric types include
• Text
• Binary
• Variant
• Variant data type is used for expressions that might return different data types, depending on the conditions.

Variables

• Variables are defined with the VAR keyword and the RETURN clause is used to return a value of the variable.
• Variable should be named using one word; variables can’t contain spaces.
• Variable scope begins with a VAR statement and ends with a matching RETURN statement.
• Once the value of a variable is evaluated, it remains constant and does not change. This behavior is similar to constants in traditional programming languages.
• Variables in DAX are executed within the context of the initial filter and row contexts.
• Use of variables help in simplifying the DAX expressions.
• DAX performs automatic conversion between strings and numbers whenever necessary.
• The following example uses the Sample-Superstore dataset to demonstrate the use of variables in measure Test Variables.