INNER JOIN vs LEFT JOIN Performance
INNER JOIN vs LEFT JOIN Performance is a SQL statement in the JOIN Types category. Performance comparison: INNER JOIN stops when no match is found. LEFT JOIN must scan all left rows regardless. The syntax is -- INNER JOIN: only matching rows. LEFT JOIN: all left + matching right. INNER is usually faster.. It returns performance pattern. A typical example: -- INNER JOIN: faster, fewer rows SELECT e.name, d.dept_name FROM employees e INNER JOIN departments d ON e.dept_id = d.id; -- Only employees that belong to a department (no match = excluded) -- LEFT JOIN: slower if most rows don't match SELECT e.name, d.dept_name FROM employees e LEFT JOIN departments d ON e.dept_id = d.id; -- ALL employees, regardless of department -- Optimization tip: -- Use INNER JOIN when you… A close relative is INNER JOIN, which returns only rows where there is a match in BOTH tables. The most common JOIN type.