SQL Checklist for Data Analysts 🚀

🌱 Getting Started with SQL

👉 Install SQL database software (MySQL, PostgreSQL, or SQL Server)
👉 Set up your database environment and connect to your data

🔍 Load & Explore Data

👉 Understand tables, rows, and columns
👉 Use SELECT to retrieve data and LIMIT to get a sample view
👉 Explore schema and table structure with DESCRIBE or SHOW COLUMNS

🧹 Data Filtering Essentials

👉 Filter data using WHERE clauses
👉 Use comparison operators (=, >, <) and logical operators (AND, OR)
👉 Handle NULL values with IS NULL and IS NOT NULL

🔄 Transforming Data

👉 Sort data with ORDER BY
👉 Create calculated columns with AS and use arithmetic operators (+, -, *, /)
👉 Use CASE WHEN for conditional expressions

📊 Aggregation & Grouping

👉 Summarize data with aggregation functions: SUM, COUNT, AVG, MIN, MAX
👉 Group data with GROUP BY and filter groups with HAVING

🔗 Mastering Joins

👉 Combine tables with JOIN (INNER, LEFT, RIGHT, FULL OUTER)
👉 Understand primary and foreign keys to create meaningful joins
👉 Use SELF JOIN for analyzing data within the same table

📅 Date & Time Data

👉 Convert dates and extract parts (year, month, day) with EXTRACT
👉 Perform time-based analysis using DATEDIFF and date functions

📈 Quick Exploratory Analysis

👉 Calculate statistics to understand data distributions
👉 Use GROUP BY with aggregation for category-based analysis

📉 Basic Data Visualizations (Optional)

👉 Integrate SQL with visualization tools (Power BI, Tableau)
👉 Create charts directly in SQL with certain extensions (like MySQL's built-in charts)

💪 Advanced Query Handling

👉 Master subqueries and nested queries
👉 Use WITH (Common Table Expressions) for complex queries
👉 Window functions for running totals, moving averages, and rankings (ROW_NUMBER, RANK, LAG, LEAD)

🚀 Optimize for Performance

👉 Index critical columns for faster querying
👉 Analyze query plans and use optimizations
👉 Limit result sets and avoid excessive joins for efficiency

📂 Practice Projects

👉 Use real datasets to perform SQL analysis
👉 Create a portfolio with case studies and projects

Here you can find SQL Interview Resources👇
https://t.me/DataSimplifier

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