What does the INNER JOIN clause do in an SQL query?

The INNER JOIN clause in an SQL query is designed to combine rows from two or more tables that share a common related column, effectively merging the data based on this relationship. When an INNER JOIN is executed, it returns only the rows where there is a match between the specified columns in the participating tables. This is particularly useful when you want to work with related data across multiple tables while excluding records that do not have corresponding matches.

For example, consider two tables: one with customer information and another with orders. An INNER JOIN can be used to retrieve only those customers who have placed orders, filtering out any customers who have not made any purchases.

In contrast, the other options describe different types of joins or behaviors in SQL. One option describes the LEFT JOIN, which includes all rows from the left table, even if there are no matches in the right table. Another option relates to a FULL OUTER JOIN, which returns all rows from both tables without filtering for matches. Lastly, another option refers to an anti-join by limiting results to unmatched rows. Understanding these distinctions helps clarify the specific role and utility of INNER JOIN within SQL queries.