DAX 2025: Major Changes Explained

Key insights

• Visual calculations: Microsoft added visual calculations in SQL Server 2025 Analysis Services to let DAX run directly on visuals, cutting the need to change semantic models.
  Functions like LOOKUP and LOOKUPWITHTOTALS let authors reference visual context and filtered lookups without inferring missing filters.
• LINEST/LINESTX and INFO functions: New statistical functions such as LINEST and LINESTX enable built-in linear regression for forecasting.
  INFO functions expose TMSCHEMA DMVs inside DAX, making model diagnostics and metadata queries easier.
• Enhanced DAX time intelligence and TOTALWTD: Power BI added custom calendar support (fiscal years, 4-5-4 retail) and week-based calculations like TOTALWTD.
  This improves accuracy for retail and finance scenarios that need nonstandard calendars.
• TMDL Visual Studio Code Extension, DAX UDFs and versioning: The TMDL VS Code extension brought semantic highlighting, autocomplete, diagnostics, and formatting for model files.
  DAX user-defined functions and Semantic Model Version History make reusable logic and model tracking easier for teams.
• Performance gains and AI agents: SSAS 2025 optimizations and Power BI improvements (grow-to-fit matrices, dynamic trendlines) sped up large models and on-the-fly calculations.
  AI-driven workflows helped automate repetitive modeling tasks and reduce human errors at scale.
• 2026 outlook and visual-first DAX: Expect deeper visual-first features, more predictive and statistical functions, and broader AI automation across authoring tools.
  Microsoft will likely continue integrating DAX, Power BI, and SSAS to simplify advanced analysis and enterprise adoption.

SQLBI recently published a YouTube video that reviews the major developments in DAX during 2025 and previews what to expect in 2026. The video serves as a concise recap of product releases, language enhancements, and authoring tools that shaped reporting and analytics this year. For readers and BI practitioners, the piece offers a clear summary of practical changes affecting both modelers and report authors.

Video Overview and Context

The video begins by framing 2025 as a year of meaningful evolution for DAX, driven largely by Microsoft updates across Power BI and SQL Server Analysis Services (SSAS). Accordingly, the author highlights monthly Power BI feature drops and previews of SSAS 2025 that together introduced new concepts such as visual calculations and expanded statistical functions. Importantly, the presentation balances feature descriptions with examples of how teams can apply the changes in real projects.

Core Language and Function Additions

First, the video emphasizes the arrival of visual calculations in SSAS 2025, which allow DAX logic to run at the visual level instead of being embedded in the semantic model. As a result, common tasks like moving averages or running totals can be executed directly on charts and tables, reducing model complexity and speeding up ad-hoc analysis. Furthermore, the new dedicated functions such as LOOKUP and LOOKUPWITHTOTALS help authors perform filtered lookups inside visuals without inferring unspecified filters.

Second, the author covers additions designed for advanced analytics, including LINEST and LINESTX for linear regression and prediction workflows. These functions expand DAX toward predictive scenarios so analysts no longer need external tools for basic trend fitting. Moreover, the video explains the arrival of INFO functions, which surface metadata and diagnostics directly in DAX, thereby simplifying troubleshooting and integration with other model components.

Time Intelligence, Authoring, and Tooling

The presentation also highlights September updates that introduced enhanced DAX time intelligence, enabling custom calendars and precise week-based calculations such as TOTALWTD. Consequently, organizations with fiscal or retail calendars can model accurate week-over-week and year-over-year metrics without awkward workarounds. Meanwhile, improvements in authoring tools—most notably the general availability of the TMDL Visual Studio Code Extension—bring semantic highlighting, diagnostics, auto-complete, and formatting that streamline development and review.

Benefits, Tradeoffs, and Governance

According to the video, the net benefit of these 2025 changes lies in increased agility and reduced development time, because teams can place targeted logic where it best serves the report consumer. Visual calculations, for example, limit model bloat and enable quicker experimentation while functions like DAX UDFs support reusable logic and cleaner model structure. At the same time, the author cautions that this flexibility introduces tradeoffs: placing logic at the visual layer can fragment rule management, making versioning and governance harder if teams are not disciplined.

Furthermore, the video stresses that AI-assisted modeling and automatic semantic model version history simplify scale, yet also raise questions about auditability and over-reliance on generated changes. Therefore, teams must balance faster creation against robust testing and documentation practices. In practice, investing in unit tests, naming standards, and centralized review will offset the risk of scattered business rules across visuals and model objects.

Challenges, Performance, and What Comes Next

Finally, the author outlines practical challenges that organizations will face when adopting these updates, including performance tuning, compatibility with legacy models, and the learning curve for new functions. Although SSAS 2025 includes performance optimizations, the video warns that complex visual calculations and regression calls can shift computation costs to the report layer, requiring careful monitoring and caching strategies. Likewise, teams must validate that AI-driven changes preserve intended behavior across scenarios.

Looking forward, the video previews 2026 as a year for maturation: vendors and teams will likely refine governance patterns, enhance testing toolsets, and formalize best practices for when to place logic in the model versus the visual. In conclusion, SQLBI’s recap provides a measured and practical view of 2025’s DAX evolution, noting both the newfound capabilities and the organizational changes necessary to use them safely and effectively.

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