DAX is a scripting language that is used to build data models on any system which supports it. It was developed by Microsoft in the late 1990s as a dialect of MDX, which was created by the MOLAP Alliance. It can be used to create reports, graphs, and even queries.
The Power BI Dax Interview Questions and Answers will help you prepare for your interview with Microsoft’s Power BI Team. The following questions are based on the level of experience candidates have with Power BI.
1. What is DAX?
Ans. DAX is a language that is used to create calculations in PowerBI. It is important to be fluent in this language because it can help you make better charts and graphs.
The DAX language was designed specifically for Microsoft Power BI and excels at the task of working with analytical data. This makes it a great choice for using on your data reports.
DAX stands for Data Analysis Expressions. It has powerful functions like FILTER, SUMIFS, and SWITCH that are not available in other languages like SQL or Excel formulas.
2. When Do You Use Sumx() Instead Of Sum()?
Ans. Sum() calculates the sum of all values in a column for a group.
Sumx() calculates the sum of all values in a column for each row in the input table.
For example, if you have a column called “Sales” and three rows, then Sum would return the sum of all sales. While Sumx would return 3 different sums (one for each row). It is important to note that if you use Sumx on a table with more than one column, then it will only calculate the sum for each row.
3. Explain about Calendarauto() Function In Dax?
Ans. This new function is designed to format dates in a way that is understandable to the user. It can be used in order to display a date in any region, with or without the time. The function can be used inside of HTML and also as part of a URL.
There are many features that make this function more appealing than the older DATE() functions. The new Calendarauto() function has five parameters that allow it to do all sorts of different things such as displaying only one day or week, displaying hours and minutes, and showing only the date by omitting AM or PM.
4. List some Aggregation Functions in Dax?
Ans. Aggregation functions are the best things to have in your arsenal if you need to pull up a specific piece of data from a dataset.
The most commonly used aggregation functions are:
5. Name the Most Useful Text Functions In Dax?
Ans. Dax has a number of text functions that provide a variety of functions that can be applied to text.
Dax enables you to concatenate strings, remove spaces, and modify dates and numbers in your texts. You also have some special functions such as the ones for changing case, sentence spacing/line spacing, and sentence capitalization. There are also some date formatting functions available in Dax.
The most useful text function in Dax is concatenating strings because it allows you to stick multiple pieces of text together without worrying about how many commas or spaces are needed between them.
6. Differentiate Distinct() And Values() In Dax?
Ans. The Distinct() function is used to count the number of unique values in a column.
The Values() function is used to extract the set of all distinct values from a column.
7. What are DAX Functions?
Ans. DAX functions are used to generate insights about data in a spreadsheet. It can be used for analysis, predictions, and for many other purposes.
DAX functions are what power some of the most exciting features in Excel such as PivotTables, slicers, OLAP cubes, pivot charts as well as many other built-in features that make data analysis easy to do.
8. What are DAX formulas?
Ans. DAX formulas are an integral part of the Power BI analytics tool. They provide a way to manipulate data, create calculated columns, and set up calculations (for example, to generate future-dated values).
DAX formulas are written in DAX language. This is a domain-specific language designed specifically for querying tabular data in Power BI and other tools. DAX formulas also support extensions of SQL that allow you to go beyond the basics.
9. What are DAX statements?
Ans. DAX statements are expressions that enable users to create calculated fields and measures in Power BI.
In order to create a DAX statement, the user needs to be familiar with SQL syntax. These statements are used widely in the data analysis process because they help make decisions easier.
10. What are DAX operators?
Ans. DAX operators are used to create calculated columns in Power BI and Power Pivot. These operators are a very powerful feature in the DAX language, and are typically an advanced topic.
DAX Operators allow you to create calculated columns that can be leveraged for insights on your data. DAX Operators can be used for any type of analysis based on your data, for example:
- Count of records
- Average price of houses sold
- Percentage difference between the first month of sales and the second month of sales
11. What are DAX Queries?
Ans. A DAX query is an expression that is used for analyzing data in a table or range. It returns a result set for one or more dimensions, rows, columns, or measures.
12. What is DAX Syntax?
Ans. DAX syntax is a type of expression language used to build calculations in Power BI. It is a superset of the DAX language, and it includes most of the functionality available in DAX as well as some additional capabilities that are not found in traditional Data Analysis Expressions.
When analyzing your data, you need to filter, group, and summarize it. In order to do this efficiently, you need to be able to write code that lets you perform these operations. This is where Dax Syntax comes in handy.
13. What are Patterns?
Ans. Patterns are a way for data visualization to find patterns in a dataset. These patterns can be found in the data by looking at the trends and differences of values.
Patterns can be created with different types of charts that Power BI offers, such as Column charts, Bar charts, Scatter Plots, and so on.
14. What are DAX Patterns?
Ans. DAX Patterns are powerful and useful tools for creating calculated columns and measures in PowerPivot.
DAX Patterns can help the user to improve their data model by adding fields that can help them to analyze data from different perspectives.
A DAX pattern is an expression of a formula that creates a new column or measure based on other columns or measures.
15. What are the benefits of using variables in DAX?
Ans. Variables are most often used in DAX for calculations. They are also used to tell the data model what values to use for a specific column.
They provide the ability to create reusable expressions and components, which can be leveraged in other formulas or visualizations. Variables can make complicated calculations simpler and less time-consuming.
Variables help us work with complex formulas that are too difficult to code by hand and debug without a formula editor tool like Visual Studio.