Skip to main content

Right Outer Join

A right join is another type of outer join, written using the RIGHT JOIN keywords. Every RIGHT JOIN
corresponds to an equivalent LEFT JOIN. The only difference is that the roles of the tables are reversed
relative to the roles in a RIGHT JOIN. That is, the right table is the reference table, so a RIGHT JOIN
produces a result for each row in the right table, whether or not it has any match in the left table.
The previous example showed the result of a LEFT JOIN . The example below is the same statement, but
with a RIGHT JOIN:

mysql> SELECT Name, Language
-> FROM Country
-> RIGHT JOIN CountryLanguage
-> ON Code = CountryCode
-> WHERE CountryCode IS NULL;
Empty set (#.## sec)

Note that the join is now being referenced to the right table CountryLanguage, which yields no results
(empty set).
Syntactically, converting a left join to a right join requires only that the order be reversed in which the
tables are named. It isn't necessary to also reverse the order in which the columns are named in the ON
clause, but it can help make the query clearer to name the columns in the same order as the tables in which
they appear.
Labels:

Comments

Post a Comment

Popular posts from this blog

PHP INTRODUCTION

                     PHP  (recursive acronym for  PHP: Hypertext Preprocessor ) is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. PHP stands for  P HP:  H ypertext  P reprocessor PHP is a server-side scripting language, like ASP PHP scripts are executed on the server PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) PHP is an open source software PHP is free to download and use Why PHP? PHP runs on different platforms (Windows, Linux, Unix, etc.) PHP is compatible with almost all servers used today (Apache, IIS, etc.) PHP is FREE to download from the official PHP resource:  www.php.net PHP is easy to learn and runs efficiently on the server side What can PHP do? Anything. PHP is mainly focused on server-side scripting, so you can...
6 comments
Read more

Storage Engine Breakdown

The following diagram represents a simplified view of the MySQL server and its interaction with the  storage engines. The following properties are storage engine dependant: • Storage Medium – Each table uses its own method of storing the data it contains. • Transactional Capabilities – Certain storage engines handle transactional processing which ensures that integrity of a database is maintained during the processing of multiple SQL statements.
Post a Comment
Read more

Managing Database Tables

1. Login in to the mysql client using the login name and password provided by your instructor. 2. View the existing databases that the MySQL Server is maintaining. SHOW DATABASES; 3. Utilize the photo_album database. USE photo_album; 4. Create the first table called customers that will store the information related to the customers who have purchased access to the online photo album CREATE TABLE customers ( email_customer VARCHAR(50) NOT NULL DEFAULT '', f_name VARCHAR(20) NOT NULL DEFAULT '', l_name VARCHAR(30) NOT NULL DEFAULT '', addr1 VARCHAR(30) NOT NULL DEFAULT '', addr2 VARCHAR(30) NULL, addr_city VARCHAR(25) NOT NULL DEFAULT '', addr_state CHAR(3) NOT NULL DEFAULT '', addr_zip CHAR(10) NOT NULL DEFAULT '', primary_phone CHAR(12) NOT NULL DEFAULT '', secondary_phone CHAR(12) NULL, term_date DATE NOT NULL DEFAULT 0, active_customer ENUM('True', 'False') NOT NULL DEFAULT ...
Post a Comment
Read more