What is true about an INNER JOIN in SQL?

An INNER JOIN in SQL is designed to retrieve rows from two or more tables that share a matching value in a specified column. This means that only those records that have corresponding entries in both tables will be included in the result set.

For example, if two tables are joined on a common key, the INNER JOIN will return rows where this key exists in both tables, effectively filtering out any rows that do not have matching entries in one of the tables. This is particularly useful when you want to analyze relationships between records in different entities where you only want relevant data that matches criteria.

The nature of INNER JOIN ensures efficient data retrieval and helps maintain data integrity since it focuses solely on overlapping data, making the combined dataset more pertinent to specific queries. Consequently, this approach is fundamental when working with relational databases where relationships among tables are crucial for analysis and reporting.