power-bi-agent-skills: Skill for Claude Code

DAX Skill

This skill helps write DAX measures, calculated columns, and calculations for Power BI semantic models.

When to Use This Skill

• Creating measures for business calculations
• Implementing time intelligence (YTD, MTD, PY comparisons)
• Writing filter context manipulations
• Building KPIs and scorecards
• Creating ranking and top N analyses
• Calculating percentages, ratios, and growth rates

DAX Formatting Standards

Follow SQLBI formatting conventions for readable, maintainable DAX:

Basic Structure

Measure Name =
VAR VariableName = Expression
VAR AnotherVariable = AnotherExpression
RETURN
    Result

Indentation Rules

• Use 4 spaces for indentation (or consistent tabs)
• Each function argument on a new line for complex expressions
• Align operators vertically

Good Formatting Example

Total Sales =
VAR SalesAmount = SUM(Sales[Amount])
VAR ReturnAmount = SUM(Returns[Amount])
VAR NetSales = SalesAmount - ReturnAmount
RETURN
    NetSales

Multi-line Function Formatting

Sales YTD =
CALCULATE(
    [Total Sales],
    DATESYTD(Date[Date])
)

Filtered Sales =
CALCULATE(
    [Total Sales],
    FILTER(
        ALL(Products),
        Products[Category] = "Electronics"
    )
)

Core DAX Patterns

Aggregation Measures

/// Total of all sales amounts
Total Sales =
SUM(Sales[Sales Amount])

/// Count of distinct customers
Customer Count =
DISTINCTCOUNT(Sales[Customer ID])

/// Average order value
Average Order Value =
AVERAGE(Sales[Order Amount])

/// Maximum sale amount
Max Sale =
MAX(Sales[Sales Amount])

Safe Division

Always use DIVIDE() instead of the / operator:

/// Profit margin percentage
Profit Margin % =
VAR Revenue = SUM(Sales[Revenue])
VAR Profit = SUM(Sales[Profit])
RETURN
    DIVIDE(Profit, Revenue, 0)

Percentage of Total

/// Sales as percentage of total
Sales % of Total =
VAR CurrentSales = [Total Sales]
VAR AllSales = CALCULATE([Total Sales], ALL(Sales))
RETURN
    DIVIDE(CurrentSales, AllSales, 0)