buildSQL:1 calls buildSQL:2.
buildSQL:2 calls buildParentSQL.
buildSQL:2 returns.
buildSQL:1 calls buildParentSQL.
("function:#" reflects recursion.)
So buildParentSQL can be called before the print in (a different) buildSQL.

On an unrelated note,
sub buildParentSQL ()
should be
sub buildParentSQL
Don't use prototypes unless you must, especially incorrect prototypes.