SQL INNER JOIN vs LEFT JOIN: When Rows Disappear
By Sharon Ben-Moshe · August 16, 2026 · 1 min read
Sharon Ben-Moshe is the founder of sqlfmt, a browser-based SQL formatter and validator with misspelled-keyword suggestions across PostgreSQL, MySQL, SQLite, SQL Server, and BigQuery.
INNER JOIN keeps matches; LEFT JOIN also retains unmatched left rows. See the result difference, the WHERE-clause trap, and safe examples.
Quick answer
INNER JOIN returns only rows with a match on both sides of the join condition. LEFT JOIN returns every row from the left table and fills right-table columns with NULL when no match exists. Choose based on whether unmatched left-side records must remain visible.
Keep reading
The Comprehensive Guide to SQL Data Types: Storage, Precision, and Cross-Dialect Portability
By Sharon Ben-Moshe · Oct 13, 2026
The complete guide to SQL data types across PostgreSQL, MySQL, SQL Server, and SQLite. Numeric precision, character sets, timestamps, and JSON.
Read postThe Definitive Guide to SQL Window Functions: Syntax, Framing, and Real-World Recipes
By Sharon Ben-Moshe · Oct 13, 2026
The comprehensive guide to SQL window functions. Master OVER, PARTITION BY, ORDER BY, window frames (ROWS vs RANGE), and ranking recipes.
Read postTry it now
Paste your SQL into sqlfmt — format, validate, and catch typos free in your browser.