Inner join is a SQL concept that allows for data from multiple tables to be combined in a single result.
It works by matching up entries from two or more tables based on the conditions that you set up – typically these are based on matching columns like names or IDs.
A practical story example of using an inner join can be seen in the workings of a furniture store.
A furniture store may have two databases, one containing customer information and another containing orders.
To generate a report of customers who have purchased products, an inner join can be used to combine the data from these two tables to produce a single record set.
The query would link the two tables based on a common column such as the customer ID, and would then return all the orders placed by that customer.
In this way, inner joins can be used to extract insights from a variety of sources.