IT Career Guides & Free Resources
Expert roadmaps, tutorials, salary guides and interview prep across Data Science, Generative AI, Python, Cloud & Analytics — written by GloryTecks trainers in Hyderabad.
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Power Query Tutorial: Transforming Data Without Code
A working tutorial for Power Query in Power BI Desktop: the applied-steps model, the profiling setting that hides problems, data types, the unpivot option that survives refresh, query folding, and how to structure queries so a report still refreshes next month.
Power Query M Language Basics for Beginners
The basics of the Power Query M language for Power BI and Excel users: how a query is built from let and in, why every step refers to the one before, case sensitivity, lists, records and tables, functions and the each shorthand, how to read the code the editor generates, and the hand edits that are worth making.
Power BI Error Handling in Power Query
Error handling in Power Query for Power BI: step-level and cell-level errors and their common causes, what Remove, Replace and Keep errors do, try with otherwise and catch for custom logic, and a real example where changing one column's type would have turned 10% of the rows into errors that Remove errors deletes.
Excel Power Query: Cleaning Data Without Code
How to clean data in Excel with Power Query instead of formulas and manual edits: combining a folder of monthly exports, fixing data types and messy text, removing duplicates without the case-sensitivity trap, merging lookup tables, unpivoting wide layouts, and turning it all into a query you refresh each month.
SQL Query Optimization Interview Questions
Optimisation questions test whether you can explain why a query is slow, not just recite rules. Each answer here is measured on two million real electricity readings in SQLite, with the plan and the work done: indexes, functions on columns, composite and covering indexes, EXISTS, and pagination.