Many of us are coming from knowing SQL before they have been introduced with DAX or many of us know how to use tabular model through reporting tool but do not know they can use DAX as query language against a tabular model.
This presentation focuses on three areas:
1. How to use DAX as a query language to select columns (columns from multiple tables and from value); Group Data; Filter Data; Join Tables; Build customized calculations/measures (like sum, window function, means)
2. How to use tracing tools to monitor the performance difference between SQL solution and DAX solution;
3. Use a real life example to demonstrate how to DAX and tabular modeling (Row Contexts vs. Filter Contexts + Bridge Table + Inactive relationship + extended table) to replace high resource consuming ETL processes
2. Why use DAX
• More secure and one source of truth
• Faster
• Easier
• Another Option
3. Use DAX to get information from Model
instead of using SQL to get data from tables
• SQL to DAX – SELECT, Grouping,Table Joins
• SQL to DAX – FILTER, Customized Measures
• Query plan and performance tuning
• ETL replacement
4. SQL to DAX – SELECT, Grouping,Table Joins
SQL
• Select
• FROM
• Top
• Join
• Having
DAX
• Evaluate
• Summarize
• Addcolumns
• TOPN
• ISBLANK
DEMO
5. SQL to DAX – FILTER, Customized Measures
SQL
• Select
• FROM
• Where
• CTE/Sub-quries/TempTable
• Join
• Having
DAX
• Filter
• Values
• All
• Calculate/CalculateTable
• ROWS
• DEFINE
DEMO
6. Query plan and performance tuning
• SQL Query Plan
• Logic/Physical Execution Plan
• SQL Query ExecutionTime Code
• SET STATISTICSTIME ON/OFF
• DAX Query plan
• DAX Studio Query Plan
• DAX ServerTiming
• DAX Studio ServerTimings
DEMO
7. Use DAX to save your ETL process time
• Inactive Relationships
• ExtendedTable
• TimeTraveling
• Blocking Filter Context
DEMO
