It will make more sense if you move assignment to $sql_content out of loop. You probably want something like

my $cor ;
my $date ;
for my $data_pair (@data_list) {
      if($data_pair->{'key'} eq 'correct'){
        $cor= $data_pair->{'value'};
      }
      if($data_pair->{'key'} eq 'date'){
        $date= $data_pair->{'value'};
      } 
}
my $sql_content = "INSERT IGNORE INTO correct SET text='".$cor."' date
+='" .$date."'";
[download]

If this is what we are looking for than try this as well

my %data_hash = map {$_->{'key'} => $_->{'value'} if ($_->{'key'} eq '
+correct' || $_->{'key'} eq 'date')} @data_list;
my $sql_content = "\nINSERT IGNORE INTO correct SET text='".$data_hash
+{'correct'}."' date='" .$data_hash{'date'}."'";
[download]