mysql - Perl DBD fetchrow_array 错误 :

Question

我在读取 MySQL 时遇到了一些奇怪的错误，我的代码是这样的:

my $sql = <<"sqleof";
select t1.name t1_name, t2.name t2_name from t2
    inner join t1 using(Id)
    where t2.Id in (select Id from t3 where t3Id='$id') 
sqleof
#here $dbh had connected correctly and done some query before this; $sql can execute pretty well on MySQL command line and return me some records.
my $execute = $dbh->prepare($sql);
$execute->execute or die "Error: $DBI::errstr\n";
my @client = $execute->fetchrow_array() or die "Error: $DBI::errstr\n";
#here I got error saying: DBD::ODBC::st fetchrow_array failed:     Unable to fetch information about the error

有什么问题？

大家好，打扰了。我找到了原因。这是一个低级别的错误，因为我使用了多个 $dbh 并且我弄错了执行名称。

    my $execute_A = $dbh->prepare($sql);
$execute_A->execute or die "Error: $DBI::errstr\n";
my @client = $execute_B->fetchrow_array()  #$execute_B here when I copied lines and modified.

您的帮助对我来说非常重要。谢谢大家。

Answer 1

替换

my @client = $execute->fetchrow_array() or die "Error: $DBI::errstr\n";

与

my @client = $execute->fetchrow_array();

你正在获取空数组，这不适合作为 ..or die .. 建议的错误检查。

.. or die .. 仅对 prepare 和 execute 方法有意义。

---

旁注，您还缺乏适当的错误检查:

my $execute = $dbh->prepare($sql) or die $dbh->errstr; # not $DBI::errstr
$execute->execute or die $execute->errstr;             # not $DBI::errstr

另外，使用sql占位符来防止sql injection .