MYSQL Table creation with default value(expression) to a column

Question

I have a Table Employee(id,name,dept_name).I want the id will alphanumeric [ffffdddaaaaa] with first 5 digit will be auto increment id and rest 4 cha

Answer 1

You could try concatenating it in your select statement instead of storing an auto increment column and an id column,

SELECT CONCAT(id, substring(name,4) FROM tbl_employee

That way you wouldn't need triggers