MySQL Joining Tables

A JOIN clause is used to combine rows from two or more tables, based on a related column between them.

Let's look at a selection from the "Orders" table:

Then, look at a selection from the "Customers" table:

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:

Example

SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderDate
FROM Orders
INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;

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and it will produce something like this:

Supported Types of Joins in MySQL

• INNER JOIN: Returns records that have matching values in both tables
• LEFT JOIN: Returns all records from the left table, and the matched records from the right table
• RIGHT JOIN: Returns all records from the right table, and the matched records from the left table
• CROSS JOIN: Returns all records from both tables