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The JOIN Clause

The JOIN Clause

Learn how to efficiently retrieve data from related tables using the SQL JOIN keyword.

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Introduction

SQL offers two distinct methods for joining tables. One method utilizes the standard WHERE clause, as demonstrated earlier. The other method employs the JOIN keyword for this purpose. The approach without the JOIN keyword may seem simpler initially but becomes intricate as queries grow in complexity. Conversely, the JOIN keyword method is more structured and easier to comprehend, particularly in complicated scenarios.

Structure of the SQL JOIN statement

The following is a typical structure of an SQL statement that uses JOIN:

SELECT columns
FROM table1
INNER JOIN table2 
ON table1.column = table2.column;
Structure of SQL JOIN

As can be seen, the JOIN clause has two components:

  1. The first one refers to the table to be joined with the one mentioned ...