What is an INNER JOIN in SQL?

An INNER JOIN in SQL is designed to combine rows from two tables where there is a matching value in both tables. This means that only the rows meeting the join condition will be included in the result set. For instance, if you have two tables, one containing customer information and another containing order details, an INNER JOIN would allow you to see only those customers who have made orders, based on a common attribute such as customer ID.

The result set will not include any customer without an associated order or any order that does not correspond to a customer. This makes INNER JOIN particularly useful for extracting relevant data that has direct relationships, ensuring that the data you’re working with is both meaningful and specifically tailored to the queries being run. The emphasis on matching records means that data integrity and relevant relationships are maintained, which is crucial for effective data analysis and reporting.