Variables and SQL functions
If you use the same identifier for an SPL variable as
for an SQL function, the database server assumes that an instance
of the identifier is a variable and disallows the use of the SQL function.
You cannot use the SQL function within the block of code in which
the variable is defined. The example in the following figure shows
a block within an SPL procedure in which the variable called user is
defined. This definition disallows the use of the USER function in
the BEGIN END block.