ALTER TABLE

The MySQL ALTER TABLE statement is used to add, modify, or drop/delete columns in a table. The MySQL ALTER TABLE statement is also used to rename a table.

The basic syntax is as follows:

ALTER TABLE table_name  ADD new_column_name column_definition  [ FIRST | AFTER column_name ]

Employee
Emp_id	Name	Surname	Salary	Dept_id
1	Rajesh	Khanna	45000	2
2	Sneha	Gupta	55000	4
3	Sandeep	Nehte	95000	1
4	Kirti	Patil	25000	3
5	Nilesh	Jadhav	45000	3
6	Dipesh	Das	35000	5
7	Kailash	Rane	62000	1
8	Kavita	Deshpande	48000	3
9	Sanjay	Datt	50000	3
10	Shruti	Hasan	78000	1

Syntax For SQL:

ALTER TABLE employee  ADD COLUMN ( 'Mobile' varchar(100) NULL );

alter table emp add column ( `dept` varchar(50) Not Null )

After Execute: 

(10 row(s) was affacted) (0 ms taken)

Result:

Emp_id	Name	Surname	Salary	Dept_id	Mobile
1	Rajesh	Khanna	45000	2
2	Sneha	Gupta	55000	4
3	Sandeep	Nehte	95000	1
4	Kirti	Patil	25000	3
5	Nilesh	Jadhav	45000	3
6	Dipesh	Das	35000	5
7	Kailash	Rane	62000	1
8	Kavita	Deshpande	48000	3
9	Sanjay	Datt	50000	3
10	Shruti	Hasan	78000	1