Stored routines are similar to stored procedures; both of them contain a block of SQL statements. There are a few differences such as a stored routine cannot return a result set and that a stored routine has to return a value and therefore, not preferred over stored procedures. Stored routines are invoked using the SELECT statement and can interchangeably be called as functions. The SHA1 function that we are using is a system-built stored routine to generate hashes for strings. Let's build a simple stored routine that would return the full name of the student when a username is passed in as a parameter, as shown in the following screenshot:

We begin by using the CREATE FUNCTION DDL command, appended by the name of the function, to create the function. This function takes the student's username as a parameter and returns the full name of the student, if the student exists. In the function...