SQL

Structured Query Language, the standard language for interacting with relational databases. It covers querying data with SELECT, modifying it with INSERT, UPDATE, and DELETE, defining schemas with CREATE and ALTER, and controlling access with GRANT and REVOKE. SQL is the universal interface to databases like PostgreSQL, MySQL, SQLite, and SQL Server.

SQL 1 🛢️ What Relational Databases Are SQL 2 🛢️ Relational Database Management Systems (RDBMS)SQL 3 🛢️ Tables, Rows, Columns, and Keys SQL 4 🛢️ SQL Categories: DDL, DML, DCL, TCL, and DQL SQL 5 🛢️ Installing SQL Environment and Client Tools SQL 6 🛢️ Creating and Dropping Databases SQL 7 🛢️ Data Types: Numeric, Character, Date, and Boolean SQL 8 🛢️ Creating Tables with CREATE TABLE SQL 9 🛢️ Modifying Tables with ALTER TABLE SQL 10 🛢️ Removing Tables with DROP TABLE and TRUNCATE SQL 11 🛢️ Primary Key and Foreign Key Constraints SQL 12 🛢️ NOT NULL, UNIQUE, and DEFAULT Constraints SQL 13 🛢️ CHECK Constraints SQL 14 🛢️ Querying Data with SELECT and FROM SQL 15 🛢️ Filtering Rows with WHERE SQL 16 🛢️ Comparison Operators SQL 17 🛢️ Logical Operators: AND, OR, and NOT SQL 18 🛢️ Range Filtering with BETWEEN and NOT BETWEEN SQL 19 🛢️ Set Filtering with IN and NOT IN SQL 20 🛢️ Pattern Matching with LIKE, ILIKE, and Wildcards SQL 21 🛢️ Handling NULL Values with IS NULL and IS NOT NULL SQL 22 🛢️ Sorting Results with ORDER BY SQL 23 🛢️ Limiting Results with LIMIT, OFFSET, and TOP SQL 24 🛢️ Removing Duplicates with DISTINCT SQL 25 🛢️ Inserting Single and Multiple Rows with INSERT INTO SQL 26 🛢️ Updating Data with UPDATE and WHERE SQL 27 🛢️ Deleting Data with DELETE SQL 28 🛢️ Column and Table Aliases with AS SQL 29 🛢️ Aggregate Functions: COUNT, SUM, AVG, MIN, MAX SQL 30 🛢️ Grouping Data with GROUP BY SQL 31 🛢️ Filtering Grouped Data with HAVING SQL 32 🛢️ Order of Execution in SQL Queries SQL 33 🛢️ Relational Joins Concept SQL 34 🛢️ Combining Data with INNER JOIN SQL 35 🛢️ Including Unmatched Rows with LEFT JOIN SQL 36 🛢️ Right Side Data with RIGHT JOIN SQL 37 🛢️ Combining All Rows with FULL OUTER JOIN SQL 38 🛢️ Cartesian Products with CROSS JOIN SQL 39 🛢️ Joining a Table to Itself with SELF JOIN SQL 40 🛢️ Combining Query Results with UNION and UNION ALL SQL 41 🛢️ Result Set Intersection with INTERSECT SQL 42 🛢️ Finding Differences with EXCEPT and MINUS SQL 43 🛢️ Subqueries in WHERE Clauses SQL 44 🛢️ Subqueries in SELECT and FROM Clauses SQL 45 🛢️ Correlated Subqueries SQL 46 🛢️ Subquery Operators: EXISTS and NOT EXISTS SQL 47 🛢️ Subquery Operators: ANY, SOME, and ALL SQL 48 🛢️ Conditional Logic with CASE WHEN Expressions SQL 49 🛢️ Handling NULLs with COALESCE and NULLIF SQL 50 🛢️ String Manipulation Functions SQL 51 🛢️ Date and Time Arithmetic Functions SQL 52 🛢️ Numeric and Math Functions SQL 53 🛢️ Data Type Conversion with CAST and CONVERT SQL 54 🛢️ Introduction to Window Functions and OVER Clause SQL 55 🛢️ Partitioning Data with PARTITION BY SQL 56 🛢️ Ranking Functions: ROW_NUMBER, RANK, DENSE_RANK SQL 57 🛢️ Tile Distribution with NTILE SQL 58 🛢️ Value Access Functions: LAG and LEAD SQL 59 🛢️ Boundary Functions: FIRST_VALUE, LAST_VALUE, NTH_VALUE SQL 60 🛢️ Aggregate Functions over Window Frames SQL 61 🛢️ Defining Window Frames: ROWS and RANGE SQL 62 🛢️ Grouping Sets: ROLLUP, CUBE, and GROUPING SETS SQL 63 🛢️ Common Table Expressions (CTE) with WITH SQL 64 🛢️ Chaining Multiple CTEs SQL 65 🛢️ Recursive CTEs for Hierarchical Data SQL 66 🛢️ Creating and Managing Views SQL 67 🛢️ Materialized Views and Refresh Strategies SQL 68 🛢️ Database Transactions and ACID Properties SQL 69 🛢️ Transaction Control: BEGIN, COMMIT, and ROLLBACK SQL 70 🛢️ Savepoints in Transactions SQL 71 🛢️ Transaction Isolation Levels and Concurrency Anomalies SQL 72 🛢️ Database Indexes Concepts SQL 73 🛢️ B-Tree, Hash, and Bitmap Indexes SQL 74 🛢️ Composite, Unique, and Partial Indexes SQL 75 🛢️ Index Maintenance, Overhead, and Unused Indexes SQL 76 🛢️ Execution Plans and Query Optimization SQL 77 🛢️ Table Scans vs Index Scans and Index Seeks SQL 78 🛢️ Database Normalization: 1NF, 2NF, and 3NF SQL 79 🛢️ Advanced Normalization: BCNF, 4NF, and 5NF SQL 80 🛢️ Denormalization Strategies for Performance SQL 81 🛢️ Entity-Relationship Modeling and Cardinality SQL 82 🛢️ User-Defined Functions (Scalar and Table-Valued)SQL 83 🛢️ Stored Procedures Creation and Execution SQL 84 🛢️ Stored Procedure Input and Output Parameters SQL 85 🛢️ Conditional Flow and Loops in Procedural SQL SQL 86 🛢️ Error Handling and Exception Control SQL 87 🛢️ Database Triggers: BEFORE, AFTER, and INSTEAD OF SQL 88 🛢️ Cursors and Iterative Processing SQL 89 🛢️ Sequences and Auto-Increment Mechanisms SQL 90 🛢️ User Access Control: GRANT and REVOKE SQL 91 🛢️ Roles, Permissions, and Data Security SQL 92 🛢️ Preventing SQL Injection Vulnerabilities SQL 93 🛢️ Row-Level Security and Data Masking SQL 94 🛢️ Working with JSON Data in Relational Databases SQL 95 🛢️ Full-Text Search and Indexing SQL 96 🛢️ Table Partitioning: Range, List, and Hash SQL 97 🛢️ Database Locks, Deadlocks, and Blocking Resolution SQL 98 🛢️ Upsert Patterns: MERGE, ON CONFLICT, and ON DUPLICATE KEY SQL 99 🛢️ Database Sharding and Read Replicas SQL 100 🛢️ Backup, Restore, and Disaster Recovery Strategies SQL 101 🛢️ Storage Engines Architecture and Page Layouts SQL 102 🛢️ Write-Ahead Logging (WAL) and Redo/Undo Logs SQL 103 🛢️ Buffer Pool Management and Page Replacement Algorithms SQL 104 🛢️ Multi-Version Concurrency Control (MVCC) Internals SQL 105 🛢️ Lock Escalation, Latching, and Two-Phase Locking (2PL)SQL 106 🛢️ Cost-Based Optimizer (CBO) Statistics and Histograms SQL 107 🛢️ Join Algorithms: Nested Loop, Hash Join, and Merge Join SQL 108 🛢️ Query Execution Engine: Volcano Iterator Model vs Vectorized Execution SQL 109 🛢️ Specialized Index Structures: GiST, GIN, BRIN, and R-Trees SQL 110 🛢️ Spatial Data Processing and PostGIS / Geospatial Extensions SQL 111 🛢️ Temporal Tables and System-Versioned Data History SQL 112 🛢️ Graph Queries in Relational Databases (Recursive & Native Graph Extensions)SQL 113 🛢️ Columnar Storage vs Row Storage for OLAP SQL 114 🛢️ Data Warehousing Concepts: Star Schema and Snowflake Schema SQL 115 🛢️ Data Vault 2.0 Modeling Mechanics SQL 116 🛢️ Slowly Changing Dimensions (SCD Types 1, 2, 3, and 6)SQL 117 🛢️ Massively Parallel Processing (MPP) Architecture SQL 118 🛢️ Distributed SQL Engines (CockroachDB, YugabyteDB, Spanner)SQL 119 🛢️ Two-Phase Commit (2PC) in Distributed Transactions SQL 120 🛢️ Consensus Protocols in Distributed Databases (Raft and Paxos)SQL 121 🛢️ Querying Unstructured Data with XML and XPath SQL 122 🛢️ Vector Search and Embeddings in SQL (pgvector, HNSW indexes)SQL 123 🛢️ Change Data Capture (CDC) with Debezium and Database Triggers SQL 124 🛢️ Foreign Data Wrappers (FDW) and Federated Queries SQL 125 🛢️ Dynamic SQL and SQL Injection Hazards in Procedural Code SQL 126 🛢️ Database Auditing, Compliance Logging, and Event Tracking SQL 127 🛢️ Cross-Database Migration Strategies and Schema Evolution SQL 128 🛢️ Database Unit Testing Frameworks (pgTAP, tSQLt)SQL 129 🛢️ Benchmarking SQL Performance (sysbench, TPC-C, TPC-H)SQL 130 🛢️ Database Driver Mechanics and Wire Protocols (PostgreSQL Protocol, MySQL Protocol)SQL 131 🛢️ Cheatsheet

Programming | Languages & Runtimes | SQL

SQL 131 🛢️ Cheatsheet
ByKandZ October 22, 2026October 22, 2026

A quick-reference for SQL syntax, functions, and behavior across PostgreSQL, MySQL, and SQL Server. Organized for lookup, not for reading. SELECT Clause Order Clause Purpose Evaluated SELECT Columns to return 5th FROM Tables to query 1st JOIN Combine tables 2nd WHERE Filter rows 3rd GROUP BY Group rows 4th HAVING Filter groups 6th ORDER BY…

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