SQL Joins Guide
The complete SQL joins guide: INNER, LEFT, RIGHT, FULL, CROSS and SELF joins, semi and anti-joins, ON vs WHERE, and join performance, with examples and result tables.
Explore the latest SQL tips and tutorials in our blog section. Learn SQL programming, database management, and query optimization.
The complete SQL joins guide: INNER, LEFT, RIGHT, FULL, CROSS and SELF joins, semi and anti-joins, ON vs WHERE, and join performance, with examples and result tables.
A categorized SQL functions list, aggregate, string, numeric, date/time, conditional and conversion functions, each with syntax, an example and the result.
A complete SQL syntax guide: statement structure, clause and logical processing order, identifiers, literals, operators, NULL logic, and cross-database differences explained.
A complete SQL tutorial for beginners: SELECT, WHERE, JOINs, GROUP BY, INSERT/UPDATE/DELETE and CREATE TABLE, taught step by step with runnable examples and their results.
Ten common database design mistakes, from missing keys and wrong data types to CSV-in-a-column and EAV abuse, each with the consequence and the fix, shown in DDL.
SQL code review best practices: catch correctness, injection, and performance issues with bad-versus-good examples, a review checklist, and a reviewer rubric.
A practical SQL performance tuning checklist: read execution plans, index the right columns, write sargable queries, keep statistics fresh, and measure every change.
The ten SQL mistakes that trip up beginners and pros alike, from = NULL and missing WHERE clauses to non-sargable filters and SQL injection, each shown with the fix and why it matters.
The complete SQL cheat sheet: every command that matters, DDL, DML, DQL, JOINs, functions, window functions and transactions, grouped by purpose with syntax and examples.