ALTER TABLE `table_name` ADD COLUMN `new_column_name` VARCHAR(255) DEFAULT "DEFUALT_VALUE" AFTER `COLUMN_NAME`;
ALTER TABLE table1 ADD COLUMN foo INT DEFAULT 0;
-- ALTER TABLE tbl_name ADD COLUMN column_name column_definition
-- [FIRST|AFTER existing_column];
ALTER TABLE office ADD COLUMN phone VARCHAR(200) DEFAULT '000' AFTER name;
ALTER TABLE office ADD COLUMN flag INT(1) FIRST;
ALTER TABLE office ADD COLUMN last_col INT(2); -- Last column is default position
-- ↓ Test it (Fiddle)