Taking the final part of your code I think you need to fix a few things before getting on to some debugging. There is a bit of confusion between a string holding the filename and an actual filehandle. I would open the output file outside the loop and close it outside the loop. Perhaps a die within the loop so we can stop and see if what we get from the db is what we expect. 
open my $fh, q{>}, $datafile 
  or die qq{cant open $datafile to write: $!\n};

 my $header_rec = join(",", @{$read_sth->{NAME}}); 
 
# print the header to the filehandle
print $fh $header_rec . "\n"; 

while (@data = $read_sth->fetchrow_array) { 

    # lets see what we have
    die @data;

    my @data = EQ_Misc::arr_replace_undef("", @data); 
    my $csv_record = join(",", @data); 
        
    # you're writing the array _and_ the record (and a dot)?
    #print $fh "@data $csv_record .\n";
    
    # did you mean?
    print $fh qq{$csv_record\n};

}
#close $datafile;
close $fh;

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In reply to Re: Writing Multiple Recordsets into a CSV file by wfsp
in thread Writing Multiple Recordsets into a CSV file by sudip_dg77

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