What is a "join"?
Here is the answer,
The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables.
Tables in a database are often related to each other with keys.A join is used to combine rows from multiple tables. A join is performed whenever two or more tables is listed in the FROM clause of an SQL statement.
SELECT suppliers.supplierid, suppliers.suppliername, orders.order_date FROM suppliers, orders WHERE suppliers.supplierid = orders.supplierid;