Daily DAX : Day 226 CONVERT

 The CONVERT function in Power BI DAX is used to convert an expression from one data type to another. It’s a straightforward way to ensure data is in the desired format for calculations, visualizations, or comparisons.

Syntax

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CONVERT(<expression>, <datatype>)

    expression: The value or column you want to convert.

    datatype: The target data type (e.g., INTEGER, DOUBLE, STRING, BOOLEAN, CURRENCY, DATETIME).

Supported Data Types

    INTEGER: Whole numbers.

    DOUBLE: Floating-point numbers (decimal values).

    STRING: Text values.

    BOOLEAN: True/False values.

    CURRENCY: Monetary values.

    DATETIME: Date and time values.

Use Cases

    Data Type Consistency:

        Ensures calculations or comparisons work correctly by converting mismatched data types. For example, converting a string representation of a number (e.g., "123") to an integer for arithmetic operations.

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    ConvertedValue = CONVERT("123", INTEGER)

    Output: 123 (as an integer).

    Formatting for Visuals:

        Convert numbers to strings to concatenate with text or display in specific formats.

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    DisplayText = CONVERT(123.45, STRING) & " units"

    Output: "123.45 units".

    Handling Mixed Data Types:

        When importing data from diverse sources, values may come as strings (e.g., "2023-01-01" or "45.67"). Use CONVERT to transform them into appropriate types like DATETIME or DOUBLE for calculations.

    dax

    DateValue = CONVERT("2023-01-01", DATETIME)

    Calculations with Currency:

        Convert numerical values to the CURRENCY type for financial calculations to ensure precision.

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    CurrencyValue = CONVERT(99.99, CURRENCY)

    Boolean Logic:

        Convert values to BOOLEAN for logical operations, such as filtering or conditional measures.

    dax

    IsTrue = CONVERT(1, BOOLEAN)

    Output: TRUE.

Example in a Measure

Suppose you have a column Sales[Amount] stored as text (e.g., "500.75"). To sum it, you need to convert it to a numerical type:

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TotalSales = SUMX(Sales, CONVERT(Sales[Amount], DOUBLE))

Notes

    Error Handling: If the conversion isn’t possible (e.g., converting "abc" to INTEGER), it returns an error. Use IFERROR or TRY to handle such cases.

    Performance: Overusing CONVERT in large datasets may impact performance. Where possible, clean data types in the data source or Power Query.

    Alternative Functions: Functions like VALUE (string to number) or FORMAT (number to string) can sometimes replace CONVERT for specific scenarios.

When to Use

Use CONVERT when you need to explicitly change a value’s data type for calculations, comparisons, or display purposes, especially when dealing with inconsistent source data.

For more details, check Microsoft’s official DAX documentation: https://learn.microsoft.com/en-us/dax/convert-function-dax