CheckValueInOtherTable Function

Code:

// Documentation Block
/*
* Function: CheckValueInOtherTable
* Aim: Checks if a selected value from one table is present in another table
* Parameter: SelectedValue - A column value from a primary table
* Return: Returns a boolean value indicating if the value exists in the other table
* Raises: An exception if the subsequent argument is not compatible
*/
DEFINE
FUNCTION CheckValueInOtherTable(SelectedValue)
    VAR ValueExists = 
        NOT ISBLANK(
            LOOKUPVALUE('SecondTable'[ColumnToCheck], 'SecondTable'[ColumnToCheck], SelectedValue)
        )
    RETURN
        ValueExists

When using this function, SelectedValue is the data to be evaluated. It is checked in the 'SecondTable' for matching values. The function returns a boolean result (TRUE if the value is found and FALSE if not). An error may be raised if SelectedValue does not match any values within ColumnToCheck.

Example:

Assuming we have two tables Orders and Products. To check if a product from Orders exists in the Products table or not, call the function like this:

CheckValueInOtherTable(SELECTEDVALUE('Orders'[ProductID]))

It is of crucial importance to understand the context in which the function is called, as results depend on the current row or filters applied. It's highly recommended to learn more about evaluation context and advanced DAX functions in courses available on Enterprise DNA Platform.