SQL Server Analysis Services Documentation

Expression Editor

The Expression Editor is a powerful tool within SQL Server Management Studio (SSMS) and Visual Studio that allows you to create and edit complex expressions for various elements in Analysis Services, such as calculated members, KPIs, calculated columns, and conditional formatting.

Purpose and Usage

The Expression Editor provides a rich environment for writing expressions using Multidimensional Expressions (MDX) or Data Analysis Expressions (DAX). It offers features like:

  • Syntax highlighting for improved readability.
  • IntelliSense for function and object name completion.
  • Error checking and validation as you type.
  • Debugging capabilities to test your expressions.
  • A function browser to easily find and understand available functions.

Key Features

  • Syntax Highlighting: Differentiates between keywords, functions, identifiers, and literals, making it easier to read and write code.
  • IntelliSense: Provides context-aware suggestions for function names, object names (cubes, dimensions, measures), and parameter names.
  • Error Checking: Real-time feedback on syntax errors and potential semantic issues.
  • Function Browser: Access to a comprehensive list of MDX and DAX functions with detailed descriptions and examples.
  • Code Snippets: Predefined code blocks for common patterns to speed up development.
  • Debugging: Allows you to set breakpoints and step through your expression logic to identify issues.

Accessing the Expression Editor

The Expression Editor can be accessed in several contexts:

  • When creating or editing calculated members in a cube.
  • When defining measures, KPIs, or calculated columns in a tabular model.
  • When setting up conditional formatting rules.

Example: Creating a Calculated Member (MDX)

This example demonstrates creating a "Yearly Sales" calculated member that sums sales for the current year.

WITH MEMBER [Measures].[Yearly Sales] AS
    Sum(
        ParallelPeriod(
            [Date].[Calendar Year].CurrentMember.Hierarchy,
            0,
            [Date].[Calendar Year].CurrentMember
        ),
        [Measures].[Internet Sales Amount]
    )
SELECT
    {[Measures].[Internet Sales Amount], [Measures].[Yearly Sales]} ON COLUMNS,
    [Date].[Calendar Year].Members ON ROWS
FROM
    [Adventure Works Cube]

Example: Creating a Calculated Column (DAX)

This example shows a DAX calculated column that concatenates a customer's first and last names.

CustomerFullName =
VAR FirstName = Customers[FirstName]
VAR LastName = Customers[LastName]
RETURN
    FirstName & " " & LastName

Best Practices

  • Use clear and descriptive names for calculated members and columns.
  • Break down complex logic into smaller, more manageable parts or variables.
  • Leverage IntelliSense to ensure correct syntax and object references.
  • Thoroughly test your expressions with sample data before deploying.
  • Refer to the MDX or DAX function reference for detailed information on available functions.