SQL Quizzes (MCQs)Level 1 The Foundations Data RetrievalBasic Retrieval SELECT, FROM, AS, DISTINCT01_DQL_BASIC Filtering Data WHERE, AND/OR/NOT, Operators02_WHERE Patterns & Ranges LIKE, BETWEEN, IN03_REGEX_OPS Sorting & Limits ORDER BY, LIMIT, OFFSET04_ORDER Null Handling IS NULL, COALESCE05_NULLS Level 2 Aggregation Summarizing DataAggregate Functions COUNT, SUM, AVG, MIN, MAX06_AGGR Grouping Results GROUP BY, Execution Order07_GROUP Filtering Groups HAVING vs WHERE08_HAVING Level 3 Relational Joins & SetsBasic Joins INNER & LEFT JOIN09_JOIN_I Advanced Joins RIGHT, FULL, CROSS JOIN10_JOIN_II Set Operations UNION, INTERSECT, EXCEPT11_SETS Level 4 DML & DDL Data & StructureModifying Data INSERT, UPDATE, DELETE12_DML Table Creation CREATE, DROP, ALTER, Types13_DDL Integrity PK, FK, UNIQUE, CHECK14_INTEGRITY Level 5 Advanced Analytics & LogicSubqueries Nested & Correlated queries15_NESTED CTEs WITH clause, Recursion16_CTES Window Functions OVER, RANK, ROW_NUMBER17_WINDOW Functions Date & String manipulation18_FUNCS Level 6 Admin OptimizationViews & Indexes Virtual Tables & Performance19_PERF Transactions ACID, COMMIT, ROLLBACK20_ACID