Mott MacDonald Power BI Developer Interview Questions and Answers

SUMX calculates the total of an expression evaluated for each row in a table, while SUM calculates the total of a column.

• SUMX is an iterator function in DAX that allows you to iterate over a table and perform calculations on each row.

• SUMX is commonly used to calculate a total based on a formula or expression applied to each row.

• SUM, on the other hand, simply calculates the total of a column without any iteration over r...read more

Time intelligence functions in DAX are used to perform calculations based on dates and times.

• Time intelligence functions help in comparing data over different time periods.

• Functions like TOTALYTD, SAMEPERIODLASTYEAR, and DATESBETWEEN are commonly used for time intelligence.

• They can be used to calculate year-to-date totals, compare values with previous periods, and more.

Calculated columns are columns created in Power BI by using DAX formulas, while measures are calculations based on the data model.

• Calculated columns are static and stored in the data model, while measures are dynamic and calculated on the fly.

• Calculated columns are used for adding new data to a table, while measures are used for aggregating data or performing calculations.

• Examples of calculated columns include adding a...read more

Numerical range parameter is a parameter that defines a range of numerical values for a specific variable or function.

• It is used to specify a range of numerical values that a parameter can take.

• It helps in filtering data based on a specific numerical range.

• For example, a numerical range parameter can be used to filter sales data for products with prices between $50 and $100.

A field parameter is a variable that is used to pass values to a function or method.

• Field parameters are used to customize the behavior of functions or methods.

• They can be used to filter, sort, or group data in Power BI reports.

• Examples include filtering data based on a specific date range or sorting data by revenue.

Calculate rolling total without resetting at specified interval

• Use DAX formula with functions like CALCULATE, FILTER, and EARLIER

• Create a measure that calculates the running total based on the current and previous rows

• Consider using variables to store intermediate results for efficiency

Use DAX function to shift one cell down in a table

• Use the LAG function in DAX to shift values down in a column

• Specify the number of rows to shift as a parameter in the LAG function

• Example: LAG([Column], 1) will shift values in 'Column' down by one row

Filters in Power BI allow users to slice and dice data to focus on specific information.

• Filters can be applied at report, page, or visual level

• Types of filters include slicers, cross-filtering, and drill-through filters

• Filters can be based on specific values, ranges, or conditions