📊 Data Analyst Interview Cheat Sheet (2025 Edition)

✅ 1. SQL Essentials
Key Concepts:
• SELECT, WHERE, GROUP BY, HAVING
• JOINs (INNER, LEFT, RIGHT, FULL)
• Window Functions (ROW_NUMBER, RANK, LEAD/LAG)
• Subqueries & CTEs
• Aggregations & Filtering

Practice Queries:
• Top 3 customers by revenue
• Monthly active users
• Running total or moving average
• Products never sold

✅ 2. Excel/Spreadsheet Skills
Key Concepts:
• VLOOKUP, XLOOKUP, INDEX-MATCH
• IF, AND, OR logic
• Pivot Tables & Charts
• Conditional Formatting
• Data Cleaning Functions (TRIM, CLEAN, TEXTSPLIT)

✅ 3. Data Visualization
Tools: Tableau, Power BI, Excel
Key Charts:
• Line chart – Trend
• Bar chart – Comparison
• Pie chart – Distribution
• Scatter plot – Correlation
• Heatmaps

Best Practices:
• Keep visuals simple & clear
• Use color intentionally
• Add titles, labels, tooltips

✅ 4. Statistics & Analytics Concepts
Key Concepts:
• Mean, Median, Mode
• Standard Deviation, Variance
• Correlation vs Causation
• Hypothesis Testing (p-value, t-test)
• A/B Testing basics
• Confidence Intervals

✅ 5. Python for Data Analysis
Key Libraries:
• Pandas – data manipulation
• NumPy – numerical ops
• Matplotlib/Seaborn – visualization
• SQLAlchemy – database access

Common Tasks:
• Read CSV/excel files
• GroupBy and aggregations
• Handling missing data
• Merge/join datasets
• Create charts

✅ 6. Business Acumen & Communication
Key Skills:
• Ask the right questions
• Translate data into insights
• Storytelling with data
• Build dashboards with KPIs
• Communicate with non-tech stakeholders

✅ 7. Tools to Know
• Excel / Google Sheets
• SQL (MySQL, PostgreSQL, etc.)
• Tableau / Power BI
• Python / R
• Jupyter / VS Code

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