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SQL

SQL queries, joins, keys and database concepts

29 articles in this category
PHP PDO: Connect to MySQL the Right Way
SQL Beginner
PHP PDO: Connect to MySQL the Right Way

Learn PHP PDO — connecting to MySQL, fetching rows, and preventing SQL injection with prepared statements.

PostgreSQL Full-Text Search
SQL Intermediate
PostgreSQL Full-Text Search

Learn tsvector, tsquery, GIN indexes, ranking, and multi-language search.

MySQL EXPLAIN: Reading Query Plans
SQL Intermediate
MySQL EXPLAIN: Reading Query Plans

Learn EXPLAIN FORMAT=JSON, EXPLAIN ANALYZE, and identifying bottlenecks.

SQL Aggregate Functions: COUNT, SUM, AVG, MIN, MAX
SQL Beginner
SQL Aggregate Functions: COUNT, SUM, AVG, MIN, MAX

Learn aggregate functions, GROUP BY to group results, and HAVING to filter groups.

PostgreSQL JSONB: Query, Index, and Operators
SQL Intermediate
PostgreSQL JSONB: Query, Index, and Operators

Learn JSONB operators, GIN indexes, jsonb_set, and performance patterns.

MySQL Indexing: B-Tree, Hash, and Composite
SQL Intermediate
MySQL Indexing: B-Tree, Hash, and Composite

Learn B-Tree, hash, composite, and covering indexes — when each type helps.