Hello All, These SQL notes are all you need to crack any Data role such as Data analyst, Business Analyst, Data Scientist, and Data Engineer!!!! Theory Topics Covered : 1. Introduction to SQL: History, importance, relational databases 2. Database basics: Tables, fields, data types, constraints 3. SQL setup: Installation, creating databases, using SQL clients 4. Key commands: DDL (CREATE, DROP), DML (SELECT, INSERT), DCL (GRANT) 5. Advanced queries: Filtering, sorting, pattern matching, aggregates 6. Joins and subqueries: INNER, OUTER joins, correlated subqueries 7. Functions: String, numeric, date, user-defined 8. Stored procedures, triggers, transactions, locks 9. Indexes, views: Creation, performance tuning 10. Security: User roles, permissions 11. Optimization: Execution plans, query tuning 12. Backup/restore, NoSQL vs SQL 13. Best practices and interview prep Complete Leetcode QnA Series 1. Easy Questions [71] 2. Medium Questions [45] 3. Hard Questions [30] SQL Interview Questions