add column in mysq
ALTER TABLE Table_name ADD Email varchar(255);
alter table add column
ALTER TABLE table ADD COLUMN column VARCHAR (255) NOT NULL AFTER column;
alter table in mysql
ALTER TABLE table_name ADD column_name datatype;
mysql alter table add column
ALTER TABLE table ADD [COLUMN] column_name column_definition [FIRST|AFTER existing_column];
Source: www.mysqltutorial.org
alter table mysql
ALTER TABLE contacts ADD last_name varchar(40) NOT NULL AFTER contact_id, ADD first_name varchar(35) NULL AFTER last_name;
Source: www.techonthenet.com
alter table query in mysql
ALTER TABLE `employees`CHANGE `emp_id` `emp_id` int(11) NULL;