Joins

JOINS:

By using Joins we can combine rows from 2 or more tables based on a related column.

 

       Emp table                                                                       

E_id	E_name	Designation
1	sai	developer
2	ram	tester
3	krish	architect

     Emp_personal table
   

E_id	E_sal	Mail
1	10000	s@gmail.com
4	20000	r@gmail.com
3	30000	k@gmail.com

  

 

1.Inner Join:

·       It displays matching data from both the tables

Select emp.*,emp_personal.* from emp Inner Join emp_personal ON emp.e_id=emp_personal.e_id;

2.Left Join:

·       Displays all records from left table and matching records from right table

Select emp.*,emp_personal.* from emp Left Join emp_personal ON emp.e_id=emp_personal.e_id;

3.Right Join:

·       Displays all records from right table and matching records from left table

Select emp.*,emp_personal.* from emp Right Join emp_personal ON emp.e_id=emp_personal.e_id;

4.Full Outer Join:

·       It displays all records from both the tables whether condition matched or not for left and right tables

Select emp.*,emp_personal.* from emp Full Join emp_personal ON emp.e_id=emp_personal.e_id;

 

5.Self Join:

·       It displays the data from the same table

·       One table consider as 2 tables

·       It Join the table by itself

EManager table

E_id	E_name	M_id
1	sai	1
2	ram	4
3	krish	5

 

 

Select *from EManager Inner Join EManager ON EManager.E_id=EManager.M_id;