Difference between INNER JOIN and OUTER JOIN in SQL

INNER JOIN and OUTER JOIN are two important concepts in SQL when it comes to combining data from multiple tables.

INNER JOIN

INNER JOIN returns only the rows where there is a match in both tables based on the join condition specified in the query. It does not include rows with no matching rows in the other table.

OUTER JOIN

OUTER JOIN, on the other hand, returns all rows from one table and only the matching rows from the other table. There are three types of OUTER JOIN: LEFT OUTER JOIN, RIGHT OUTER JOIN, and FULL OUTER JOIN.

Key Differences

• INNER JOIN only returns rows with matching values in both tables, while OUTER JOIN returns all rows from one table and matching rows from the other.
• OUTER JOIN can include rows with NULL values in the non-matching columns, whereas INNER JOIN does not include those rows.
• There are different types of OUTER JOIN, offering more flexibility in specifying which rows to include in the result set.

Understanding the differences between INNER JOIN and OUTER JOIN is crucial for effective database queries and data retrieval in SQL.