Daily DAX : Day 138 CONTAINSSTRING

 The CONTAINSSTRING function in Power BI's DAX (Data Analysis Expressions) language is a handy tool for checking whether a specific substring exists within a given text string. It’s case-sensitive and returns a simple TRUE or FALSE result, making it great for filtering, conditional logic, or flagging data based on text patterns.

Here’s the basic syntax:

CONTAINSSTRING(text, search_text)

    text: The string you’re searching in (e.g., a column or a text value).

    search_text: The substring you’re looking for.

For example, if you have a column called ProductDescription and want to check if it contains the word "Premium," you’d write:

CONTAINSSTRING('Products'[ProductDescription], "Premium")

If "Premium" is in the description, it returns TRUE; otherwise, FALSE.

Main Use Case

The primary use case for CONTAINSSTRING is text-based filtering or categorization. It’s especially useful when you need to identify rows in a dataset that contain specific keywords or phrases without worrying about their exact position. For instance:

    Customer Feedback Analysis: Flag comments containing words like "excellent" or "poor" to gauge sentiment.

    Product Segmentation: Identify products with certain attributes in their names or descriptions (e.g., "Organic" or "Deluxe").

    Data Validation: Check if error logs contain specific codes or terms for troubleshooting.

Unlike functions like SEARCH (which returns the position of a substring and errors out if it’s not found), CONTAINSSTRING is simpler and more forgiving—it just tells you if the substring is there. It’s a go-to when you don’t need the "where" and just want the "if."