DAX Query Basics - Data Types, Syntax & Functions

Last Updated: 15th October 2025

DAX (Data Analysis Expressions) is a formula language used in:

• Power BI
• Power Pivot (Excel)
• SSAS Tabular Models

It helps you create custom calculations — like totals, averages, growth rates, comparisons, etc.

🗣 Hinglish Tip: DAX ko samjho Excel formulas ka “Power BI version” — par zyada smart aur dynamic!

✏ DAX Syntax

DAX formula = Function Name + Arguments

NewColumn = FunctionName(TableName[ColumnName])

Example 👇

Total Sales = SUM(Sales[Amount])

💡 Syntax Breakdown:

SUM → Function name

( ) → Parentheses to enclose arguments

Sales[Amount] → TableName[ColumnName]

You can also create:

Calculated Columns → work row-by-row

Measures → work on aggregated data (dynamic)

-- Example of a Measure
Total Sales = SUM(Sales[Amount])

-- Example of a Calculated Column
Profit = Sales[Amount] - Sales[Cost]

DAX Data Types

DAX supports these core data types:

🗣 Tip: DAX automatically converts data types when needed (called implicit conversion).

🔣 Writing DAX — General Syntax Rules

• Function names are not case-sensitive
• Always use square brackets [ ] for columns
• Use double quotes " " for text values
• Use comma (,) to separate function arguments
• Comments:

-- Single-line comment

/* Multi-line
   comment */

🧮 Categories of DAX Functions

DAX has 250+ functions, but here are the main categories you'll use daily:

We will cover these in more detail in the coming sections.