But you are passing them inside single quotes, and what goes inside single quotes is not interpolated.

Wrong. The single quotes are inside a double-quoted string.

The original version is not best practice, but it won't fail until one of the interpolated variables contains an embedded quote.

my $name = 'Larry';
my $sql = "Insert into Users (name) values ('$name')";
print $sql;
# Insert into Users (name) values ('Larry')
[download]