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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SQL Optimization for Data Engineers
How to make SQL queries faster with evidence: reading the query plan, a full scan versus a composite index versus a covering index measured in engine steps on 2.9 million real taxi rows, why wrapping a column in a function cost twenty times more work, and the habits that carry over to SQL Server and warehouses.
Pandas vs SQL for Data Analysis: When to Use Which
Pandas versus SQL for data analysis, compared on the same real dataset: identical answers from a GROUP BY and a groupby, a moving average as a window function and as rolling, a pivot that is one line in pandas and many in SQL, and why filtering in the database first matters when data is large.
Connecting Power BI to SQL Server: A Step-by-Step Guide
Connecting Power BI to SQL Server, step by step: preparing a reporting view, the connector's settings and advanced options, authentication and certificate errors, keeping Power Query steps folding back to SQL Server, native SQL statements, checking row counts, gateway refresh and troubleshooting.
SQL Joins Interview Questions Explained
Join questions in interviews are rarely about syntax. They test whether you can predict how many rows come back. These nine questions, each answered with a query on three million real New York taxi trips, cover anti-joins, ON versus WHERE, NOT IN with NULLs, fan-out, self-joins, calendars and full outer joins.
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.