DAX Lookup and Language Translation Overview

Code Analysis and Breakdown

The provided code snippet is written in DAX (Data Analysis Expressions), which is a formula language used in Power BI, SQL Server Analysis Services, and Power Pivot in Excel.

LOOKUPVALUE('Label Translation'[Label Text],
            'Label Translation'[Label Name], "Total Pressure",
            'Label Translation'[Language ID], FIRSTNONBLANK('Label Translation'[Language ID], "en-US"))

Purpose of the Code

The LOOKUPVALUE function retrieves a single value from a specified column, in this case, Label Text, based on criteria defined for other columns within the same table.

Components of the Code

LOOKUPVALUE Function

The LOOKUPVALUE function in DAX is used to return the value in a result column for the row that meets all the specified conditions. The basic syntax is:

LOOKUPVALUE(result_column, search_column1, search_value1[, search_column2, search_value2, ...])

• result_column: The column from which to return the value.
• search_column1, search_value1: The first column and value pair used as a condition.
• search_column2, search_value2: Additional column and value pairs can be added.

Detailed Breakdown

1. Result Column:

   • 'Label Translation'[Label Text]: This is the column from which the function retrieves the value.

2. First Search Condition:

   • 'Label Translation'[Label Name]: The first condition column.
   • "Total Pressure": The search value for the first condition. The function looks for rows where Label Name is "Total Pressure".

3. Second Search Condition:

   • 'Label Translation'[Language ID]: The second condition column.
   • FIRSTNONBLANK('Label Translation'[Language ID], "en-US"): This portion ensures that the Language ID is the first non-blank value, defaulting to "en-US" if no non-blank values are found.

FIRSTNONBLANK Function

The FIRSTNONBLANK function returns the first non-blank value in a column. Its syntax is:

FIRSTNONBLANK(column, expression)

• column: The column to search.
• expression: An expression to evaluate.

In this context, it defaults to "en-US" if no non-blank values exist in the 'Label Translation'[Language ID] column.

Key Concepts

1. LOOKUPVALUE:

   • Retrieves values from a specified column based on given conditions.
   • Similar to a VLOOKUP in Excel.

2. FIRSTNONBLANK:

   • Useful for avoiding errors due to blank values.
   • Ensures a default fallback value.

Additional Example

Consider an alternative example to illustrate a similar concept:

LOOKUPVALUE('Sales'[Revenue], 'Sales'[Product ID], 101, 'Sales'[Region], "North America")

This code retrieves the Revenue value for the product with Product ID 101 sold in the "North America" region.

Conclusion

The provided DAX code is used to find the translated label text for "Total Pressure" in the specified language, defaulting to "en-US" if necessary. Understanding and effectively using LOOKUPVALUE and FIRSTNONBLANK can significantly aid in data analysis tasks within Power BI and similar tools. For further learning, courses on the Enterprise DNA Platform focusing on DAX will be beneficial.