Tagged: SQL
26 articles tagged SQL across all clusters on CodeWalkers.
Programming Learning Paths
Ordered programming learning paths for PHP, SQL, APIs, browser projects, and future language tracks.
SQL UNION and UNION ALL: Combine Compatible Result Sets
Use SQL UNION and UNION ALL to combine compatible result sets without confusing them with joins.
SQL Transactions and ACID
Understand transactions, commits, rollbacks, and the ACID model for reliable database writes.
SQL Databases
Guides to the common SQL database engines: MySQL, PostgreSQL, SQLite, and MariaDB, and when to reach for each.
Build a Mini Chat App with PHP
Modernize the old PHP mini-chat pattern with PDO, sessions, CSRF protection, escaped output, and a clear polling or SSE boundary.
SQL vs NoSQL: Relational vs Document, Key-Value, and Graph
Compare relational SQL with document, key-value, graph, wide-column, and search models through workload and ownership criteria.
Build Dynamic Sites with PHP and MySQL
Start the PHP web-app path with one small dynamic site, a clean data model, PDO queries, and plain request handling.
Add News and Comments with PHP and MySQL
Extend a small PHP/MySQL app with news posts, comments, simple moderation, PDO writes, and escaped output.
SQL Comparisons
Honest SQL database comparisons: MySQL vs PostgreSQL vs SQLite, MySQL vs MariaDB vs MaxDB, and SQL vs NoSQL.
Import CSV into SQL: Load, Validate, and Transaction Paths
Move CSV data into MySQL, PostgreSQL, SQLite, or a PHP/PDO import flow without losing validation, transactions, or schema discipline.
MySQL vs PostgreSQL vs SQLite
Compare MySQL, PostgreSQL, and SQLite by deployment, write concurrency, data rules, JSON, search, and recovery needs.
SQL Schema Design: Keys, Constraints, Indexes, Migrations
Design relational tables through a worked normalization example, then add stable keys, constraints, indexes, and safe migrations.
PHP and MySQL with PDO
Use PDO prepared statements to connect PHP to MySQL safely and keep SQL input handling clear.
SQL Indexes and Query Optimization
Learn what SQL indexes do, what they cost, and how to use EXPLAIN without guessing.
PostgreSQL: Roles, JSONB, Indexes, Backups, and Upgrades
Learn where PostgreSQL fits, how roles and schemas separate access, how JSONB works with indexes, and how to plan backups and major upgrades.
SQL Joins: Inner, Left, Self Joins, and Explicit Syntax
Understand inner joins, left joins, self joins, and why explicit JOIN syntax makes SQL easier to review.
MySQL: Restricted Users, InnoDB, Backups, and Major Upgrades
Learn where MySQL fits, how to create a restricted application user, how InnoDB transactions work, and how to plan backups and upgrades.
PHP Pagination with Previous and Next Links
Build previous and next links in PHP with validated page numbers, PDO queries, LIMIT/OFFSET, and a clear path to cursor pagination.
SQLite: CLI Inspection, WAL Mode, Backup, and Migration
Learn where SQLite fits, how to inspect a database with the CLI, what WAL changes, and how to back up and migrate a single-file database.
Storing Images in a Database
Compare database BLOBs with external image storage through transaction, delivery, backup, memory, security, and cleanup requirements.
MySQL vs MariaDB vs MaxDB
Compare MySQL, MariaDB, and SAP MaxDB by lineage, support context, compatibility testing, and migration criteria.
Common SQL Interview Questions
Practise SQL interview questions grouped by beginner, intermediate, and advanced level, with model answers and a self-test quiz.
The LAMP Stack Explained
What the LAMP stack is, why Linux, Apache, MySQL or MariaDB, and PHP still run so much of the web, and when to reach for it.
Add Search to a PHP and MySQL App
Extend the PHP web-app path with prepared search queries, pagination, indexed SQL, and a clean upgrade path to full-text search.
MariaDB: MySQL Compatibility, Engines, and Config Files
Understand MariaDB's relationship to MySQL, current release model, storage engines, install/config differences, and when a PHP or SQL project should consider it.
SQL Guide: Queries, Joins, Schema Design, and Databases
A practical SQL guide for joins, schema design, indexes, transactions, database choices, CSV imports, search, PostgreSQL, MySQL, SQLite, MariaDB, and interview-ready reasoning.