How can I separate the undef data and NULL data?
Hmmmm.... This question doesn't make sense to me, for 'undef' is a concept in the Perl domain, and 'NULL' is a concept in the SQL domain. This means that in Perl you don't have NULL, and in SQL, you don't have undef. From DBI:

NULL values are represented by undefined values in Perl

-- 
Ronald Fischer <ynnor@mm.st>

In reply to Re: Perl DBI NULL and undef by rovf
in thread Perl DBI NULL and undef by chefchanyu

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