Overview
In this two-day course, students will be introduced to using Data Analysis Expressions (DAX), which is the expression language that is used to create custom calculations in the `
Power BI
Data model. The course covers some of the theoretical underpinnings of the data model and DAX, but the emphasis is on using DAX to solve common business problems. Students will learn how to write their own calculated columns, measures, and tables, how to visualize the way Power BI computes DAX calculations, and how to troubleshoot custom code. This instructor-led course consists of a combination of lecture, demonstrations, and hands-on labs.
Software Used During the Class
The standard lab setup for this class consists of a Window 10 PC with Power BI Desktop and DAX Studio installed.
Audience
This course is intended for business users who have been using Power BI to build analytic solutions and are ready to take advantage of the power and flexibility that DAX provides. Learning DAX is a very common “next step” for experienced Power BI users.
Prerequisites
Although experience with Power BI Desktop is not strictly required for this class, students with at least some familiarity will be better equipped to get the most out of the lab work.
DAX functions that are covered in this class include:
- Date and time functions: CALENDAR(), DATE(), DATEDIFF(), NOW(), WEEKDAY(), WEEKNUM(), YEAR(), MONTH(), DAY()
- Filter functions: ALL(), ALLCROSSFILTERED(), ALLEXCEPT(), ALLSELECTED(), CALCULATE(), CALCULATETABLE(), FILTER(), KEEPFILTERS(), LOOKUPVALUE(), REMOVEFILTERS()
- Information functions: CONTAINS(), HASONEFILTER(), HASONEVALUE(), ISBLANK(), ISEMPTY(), ISERROR(), USERNAME()
- Logical functions: AND(), COALESCE(), IF(), IF.EAGER(), IFERROR(), NOT(), OR(), SWITCH(), TRUE(), FALSE()
- Math and Statistical Functions: DIVIDE(), SUM(), SUMX(), AVERAGE(), AVERAGEX(), COUNT(), COUNTBLANK(), COUNTROWS(), COUNTX(), DISTINCTCOUNT(), MAX(), MAXX(), MEDIAN(), MEDIANX(), MIN(), MINX(), RANKX()
- Table manipulation functions: CROSSJOIN(), DATATABLE(), NATURALINNERJOIN(), VALUES()
- Text functions: CONCATENATEX(), FIND(), LEFT(), LEN(), MID(), REPLACE(), SEARCH(), TRIM(), VALUE()
- Time intelligence functions: DATEADD(), DATESBETWEEN(), DATESMTD(), DATESQTD(), DATESYTD(), PARALLELPERIOD(), SAMEPERIODLASTYEAR(), TOTALMTD(), TOTALQTD(), TOTALYTD
COURSE OUTLINE
Getting started with DAX
What is DAX?
Basics of DAX syntax
Creating a calculated column
Creating a calculated measure
Creating a calculated table
Differences in evaluation context
Rules of evaluation
Working with variables
Commenting your code
Testing your code
Performing basic calculations
Implicit measures
Adding quick measures
Doing basic math
Using logic in your calculations
Aggregating and summarizing data
Working with DAX data types
Working with context in the data model
Context defined
Data modeling basics
Introduction to dimensional modeling
Relationships and their effect on the evaluation context
Getting data from other tables using RELATED and RELATEDTABLE
Modifying the context using CALCULATE
Looking up data without using relationships
Performing more advanced calculations
Handling errors gracefully
Using DAX iterator functions
Using table manipulation functions
Troubleshooting your calculations using the Performance Analyzer and DAX Studio
Working with time
Performing date calculations
Working with date tables
Generating a date table with the CALENDAR() function
Defining custom operating periods
YTD, QTD, and MTD calculations
Custom to-date calculations
Finding year-over-year change
Finding moving averages
Enhancing the user experience
Controlling visibility of your measures
Using What-if parameters
Adding banding
Using DAX to provide row-level security
