https://dataanalystinterview.com/data-analyst/data-analyst-portfolio-funnel-case-study/ 2026-09-14T18:17:48Z Interview Preparation en Write a Data Analyst Portfolio Case Study Without Inventing Impact 2026-09-14T07:14:35Z Blog https://dataanalystinterview.com/data-analyst/pandas-merge-duplicate-revenue-validation/ 2026-09-14T18:17:43Z Interview Preparation en Pandas Merge Mistakes: Prevent Duplicate Revenue 2026-09-14T07:14:30Z Blog https://dataanalystinterview.com/data-analyst/investigate-revenue-drop-sql-worked-example/ 2026-09-14T18:17:36Z Interview Preparation en Investigate a Revenue Drop with SQL: A Worked Example 2026-09-14T07:14:24Z Blog