How to join more than two table sql

Joining Tables:

                        Join is used to relate multiple table. It is used to avoid redundant data. It just follow the concept Divide and Conquer. Instead maintaining the whole redundant data in one table and wasting of storage. we divide table into multiple part and as join the table. we join the table as what information is need. Also join save store memory, as below example table for employee thomas the dept_id is 1, instead maintaining  the character storage. 

Lets join 6 table 

employee

id	Emp_name	Dept_id
1	Thomas	1
2	Jebas	2
3	Mark	3
4	Harry	4

 In this table employee,  the address of employee are divided as below.

Deparment

Dept_id	Dept_name
1	Director
2	Manager
3	Employee
4	HR

country_table

country_id	country_name
1	INDIA
2	UK
3	US

state_table

state_id	country_id	state_name
1	1	Tamil Nadu
2	1	Andhra Pradesh
3	1	Kerala
4	3	New York
5	2	England

city_table

city_id	state_id	city_name
1	1	Tirunelveli
2	1	Tuticorin
3	3	Thiruvananthapuram
4	4	Beacon
5	5	Gloucester

Address_table

Emp_id	city_id	state_id	country_id
1	1	1	1
2	2	1	1
3	4	4	3
4	5	5	2

SELECT  Emp_name

,dept_name

      ,city_name

      ,state_name

      ,country_name

  FROM Employee, dept_table,

 city_table,

 state_table,

 country_table,

 Adresss_table

whereEmployee.dept_id =dept_table.dept_id AND 

Employee.id=Adresss_table.address_id

AND Adresss_table.city_id =city_table.city_id 

AND Adresss_table.state_id =state_table.state_id 

AND Adresss_table.country_id =country_table.country_id 

This statement return as  

Emp_name	dept_name	city_name	state_name	country_name
Thomas	Director	Tirunelveli	Tamil Nadu	INDIA
Jebas	Manager	Tuticorin	Tamil Nadu	INDIA
Mark	Employee	Beacon	New York	US
Harry	HR	Gloucester	England	UK

Also we filter the result  as we need

SELECT  Emp_name

,dept_name

      ,city_name

      ,state_name

      ,country_name

  FROM Employee, dept_table,

 city_table,

 state_table,

 country_table,

 Adresss_table

whereEmployee.dept_id =dept_table.dept_id AND 

Employee.id=Adresss_table.address_id

AND Adresss_table.city_id =city_table.city_id 

AND Adresss_table.state_id =state_table.state_id 

AND Adresss_table.country_id =country_table.country_id 

AND country_table.country_name='INDIA'

This statement the employee whose country is india

Emp_name	dept_name	city_name	state_name	country_name
Thomas	Director	Tirunelveli	Tamil Nadu	INDIA
Jebas	Manager	Tuticorin	Tamil Nadu	INDIA

SELECT  Emp_name

,dept_name

      ,city_name

      ,state_name

      ,country_name

  FROM Employee, dept_table,

 city_table,

 state_table,

 country_table,

 Adresss_table

whereEmployee.dept_id =dept_table.dept_id AND 

Employee.id=Adresss_table.address_id

AND Adresss_table.city_id =city_table.city_id 

AND Adresss_table.state_id =state_table.state_id 

AND Adresss_table.country_id =country_table.country_id 

AND country_table.country_name='INDIA' 

AND city_table.city_name='Tirunelveli'.

This statement the employee whose city name is Tirunelveli

Emp_name	dept_name	city_name	state_name	country_name
Thomas	Director	Tirunelveli	Tamil Nadu	INDIA

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