Certifications, Education, and Formal Training Questions

Situation: I completed the "Advanced SQL for Data Analysts" certification on Coursera over the past six months to close a skills gap I noticed while maintaining slow dashboards and complex ad-hoc queries.

Task: I wanted practical techniques for query performance, advanced window functions, CTEs, query refactoring, and data modeling so I could deliver faster, more maintainable reporting.

Action:

• Invested ~60 hours (12 weeks × 5 hrs/week): video lectures, graded assignments, and two capstone projects.
• Covered topics: indexing and execution plans, joins and set operations, CTEs and recursive queries, window functions (ROW_NUMBER, LAG/LEAD, SUM OVER), query optimization techniques, basic data modeling and normalization.
• Applied learning immediately: refactored a slow revenue dashboard query that used multiple correlated subqueries. I rewrote it using CTEs and window functions, added appropriate indexes to the fact table, and replaced a Cartesian join with a proper join on surrogate keys.

Result: Dashboard refresh time dropped from ~8 minutes to 50 seconds (85% improvement). Stakeholders received near-real-time daily reports; I also documented the new query patterns and ran a 30-minute lunch-and-learn to share best practices with the analytics team.

This structured learning gave me concrete tools to improve performance and reproducibility, and I now include query plan checks and index considerations as part of every dashboard optimization.