Notice that the "CustomerID" column in the "Orders" table refers to the "CustomerID" in the "Customers" table. The relationship between the two tables above is the "CustomerID" column. Then, we can create the following SQL statement (that contains an INNER JOIN), that selects records that have matching values in both tables:
Today, the most common method for joining data from multiple tables is with the special operator JOIN, also known as INNER JOIN. To see how it works, we will use the same two tables from the warehouse database, which you can find below for convenience.
SQL joins are fundamental tools for combining data from multiple tables in relational databases. For example, consider two tables where one table (say Student) has student information with id as a key and other table (say Marks) has information about marks of every student id.
There are many categories of joins in SQL that let users combine rows from two or more tables based on different types of conditions, according to our requirement. These different types of Join in SQL are explained thoroughly below. SQL gives you an option of choosing from the following seven types of joins: