You move beyond dragging and dropping in Power BI or Tableau. You learn to shape complex datasets directly in SQL Server, using window functions to calculate moving averages and percentiles. Your reports become faster and more maintainable.
You cannot hack your way through relational theory. You must understand it. Whether you are aiming for a promotion, a certification, or simply the respect of your peers, buying this book (or renting it via O’Reilly Online) and working through every single exercise is the highest-leverage activity you can do for your career in data. itzik ben-gan t-sql fundamentals
He is the primary founder of SolidQ, a global training and consulting firm, and has been instrumental in shaping how professional developers think about set-based logic versus procedural programming. When Itzik speaks about query optimization or logical query processing, the product group at Microsoft listens. You move beyond dragging and dropping in Power BI or Tableau
You learn to read execution plans. Because you understand logical processing, you can look at a plan and immediately identify the bottleneck—whether it’s a missing index or a poorly written OR predicate. You cannot hack your way through relational theory