Example to output the number of output records to a header

With the data matching function, input file can be joined with another file by generating combined records if there is a shared field between the two files (and therefore the files are "related"). Note that the existence of the shared field (namely relation) is a prerequisite for matching. Therefore, if there is no such relation, two files cannot be joined. However, by using a virtual table query, it becomes possible to match an input file with a matching file unrelated to the file.