Chapter 5, Problem 15RQ

Program Plan Intro

Join:

The “JOIN ON” syntax is usually used to join two or more than two tables. This syntax usually works with “WHERE” clause. The keyword “JOIN” is normally placed between the table names in the SQL FROM clause. The keyword “ON” includes the matching key values.

Inner join:

• Rows included in inner join: Inner join is the joining method that gets all rows with matching values in both the tables.
• This does not include non-matching rows.
• Clause used in inner join operation: Inner join operation uses “INNER JOIN” clause to join the tables.

Syntax:

SELECT column_Name(s) FROM table_Name1 INNER JOIN table_Name2 ON table_Name1.column_Name = table_Name2.column_Name;

Cartesian product:

• It is the formal name for multiplying two tables.
• It is also called as “CROSS JOIN” that returns the result that contains the product of number of rows in the first and second table.
• If “WHERE” clause is used in “CROSS JOIN” then it works like “INNER JOIN”.

Syntax:

SELECT table_Name1.column_Name1, table_Name2.column_Name2… FROM table_Name1, table_Name2,…;