Difference between right join and inner join?

Answer 1

Hi,

Natural Join: It is combination or combined result of all the columns in the two tables.

It will return all rows of the first table with respect to the second table.

Inner Join: This join will work unless if any of the column name shall besxame in two tables

Answer 2

Inner join is just normal join you can also write just using where clause. where as 'outer join' has two types: 1: Left Outer Join If you want to query from two tables with a left outer join, you can use the LEFT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a left outer join from two tables: departments and employees. The join condition is that the manager ID in the departments table equals to the employee ID in the employees table: SQL> set NULL 'NULL'

SQL> SELECT d.department_name, e.first_name, e.last_name

2 FROM departments d LEFT OUTER JOIN employees e

3 ON d.manager_id = e.employee_id;

DEPARTMENT_NAME FIRST_NAME LAST_NAME

-------------------- -------------------- --------------

Administration Jennifer Whalen

Marketing Michael Hartstein

Purchasing Den Raphaely

Human Resources Susan Mavris

Shipping Adam Fripp

IT Alexander Hunold

......

Treasury NULL NULL

Corporate Tax NULL NULL

Control And Credit NULL NULL

Shareholder Services NULL NULL

Benefits NULL NULL

Manufacturing NULL NULL

Construction NULL NULL

...... 2: Right Outer join; This is opposite to the Left outer join. Right outer join returns all the rows of 2nd table thought it doesn't have the matching rows in the left side table of where clause. ex: If you want to query from two tables with a right outer join, you can use the RIGHT OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a right outer join from two tables: departments and employees. The join condition is that the manager ID in the departments table equals to the employee ID in the employees table: SQL> set NULL 'NULL'

SQL> SELECT d.department_name, e.first_name, e.last_name

2 FROM departments d RIGHT OUTER JOIN employees e

3 ON d.manager_id = e.employee_id;

DEPARTMENT_NAME FIRST_NAME LAST_NAME

-------------------- -------------------- ---------------

Administration Jennifer Whalen

Marketing Michael Hartstein

Purchasing Den Raphaely

Human Resources Susan Mavris

Shipping Adam Fripp

IT Alexander Hunold

......

NULL Clara Vishney

NULL Jason Mallin

NULL Hazel Philtanker

NULL Nanette Cambrault

NULL Alana Walsh

NULL Karen Partners

NULL Bruce Ernst

......

Answer 3

* LEFT JOIN: Return all rows from the left table, even if there are no matches in the right table * RIGHT JOIN: Return all rows from the right table, even if there are no matches in the left table

Answer 4

A right outer join returns all the values from the right table and matched values from the left table and a NULL in case of no matching.

An inner join only shows matching records from both tables. If there is a null on one side, then the record from the other table will not be shown.

Answer 5

self join uses simal table with alias and inner join uses two or more different table