MySQL + SQL · Lesson 67

INNER JOIN in MySQL

INNER JOIN

INNER JOIN returns only the rows that have a match in BOTH tables. Unmatched rows are dropped.

Example

SELECT s.name, c.class_name
FROM students s
INNER JOIN classes c ON s.class_id = c.class_id;

A student with a class_id that has no matching class is NOT shown.

Table Aliases

students s gives the table a short alias s, so you write s.name instead of students.name.

Summary

INNER JOIN = only rows matching in both tables.
Use ON to state the matching condition; aliases shorten queries.