use strict;

my (@fields, @data);

while (<DATA>) {
    chomp;
    my ($field, $value) = split;
    next if !defined $value;
    push @fields, $field;
    push @data, $value;
}

my $insert = "INSERT INTO foo ("
    . join(",", @fields)
    . ") VALUES ("
    . join(",", map { qq("$_") } @data)
    . ");";

print "$insert\n";

__DATA__
 col1  data_line1
    col2  data_line2
    col3  data_line3
          data_line4
          data_line5
          data_line6
    col4  data_line7

##</code><code>##

my $fieldlist = join(",", @fields);
my $placeholders = join(",", map {'?'} @fields);

my $insert = qq{
	INSERT INTO foo ($fieldlist) 
	VALUES ($placeholders)};