Question

我需要帮助编写perl DBD :: CSV包的SQL语句。我想合并2个CSV文件，如下所示：

file1.csv：

VM_Name,VM_Cluster,VM_Zone
VM1," Cluster4","Zone3"
VM2," Cluster3","Zone4"
VM3," Cluster2","Zone1"
VM4," Cluster1","Zone2"

file2.csv：

VM_Name,vFiler_IP,vFiler_Zone
VM1," 10.10.10.10","Zone5"
VM2," 10.10.10.11","Zone8"
VM3," 10.10.10.12","Zone8"
VM4," 10.10.10.13","Zone8"

Mergerd文件应如下所示：

VM_Name,VM_Cluster,VM_Zone,vFiler_IP,vFiler_Zone
VM1," Cluster4","Zone3"," 10.10.10.10","Zone5"
VM2," Cluster3","Zone4"," 10.10.10.11","Zone8"
VM3," Cluster2","Zone1"," 10.10.10.12","Zone8"
VM4," Cluster1","Zone2"," 10.10.10.13","Zone8"

这是我的perl代码：

#!/usr/bin/perl -w

use strict;
use Data::Dump qw/dump/;
use DBI;

my $dbh = DBI->connect ("dbi:CSV:",
                        "", "", 
                        {   
                              f_dir       =>      './Desktop',
                              f_schema    =>       undef,
                              f_ext       =>      '.csv/r',
                        }   
                    ) or die " Cannot create Database Handle: $DBI::errstr()";
$dbh->{RaiseError} =1 ;

my $table1 = "file1";
my $table2 = "file2";


my $query = "SELECT $table1.VM_Name, $tabel1.VM_Cluster, $table1.VM_Zone, $table2.vFiler_IP, $table2.vFiler_Zone FROM $table1 join $table2  WHERE $table1.VM_Name = $table2.VM_Name";
my $result = $dbh->selectall_arrayref ($query);
print dump ($result);

输出应该是我在“[]”括号中的支出，但我得到的是一个空的“[]”括号，如下所示：

[]

我猜我写的“$ query”语句是错误的。你能帮忙找出这项工作的正确查询吗？

感谢。

Answer 1

我不确定DBD :: CSV如何尊重SQL，但通常如果您join，您还应该说on要加入的内容：

select $table1.VM_Name,
       $tabel1.VM_Cluster,
       $table1.VM_Zone,
       $table2.vFiler_IP,
       $table2.vFiler_Zone
  FROM $table1 join $table2  
               ON $table1.VM_Name = $table2.VM_Name

Answer 2

您的SQL语句中存在拼写错误。改变这一行：

my $query = "SELECT $table1.VM_Name, $tabel1.VM_Cluster, $table1.VM_Zone, $table2.vFiler_IP, $table2.vFiler_Zone FROM $table1 join $table2  WHERE $table1.VM_Name = $table2.VM_Name";
                                      ^--- $table1

您需要使用：

my $query = "SELECT $table1.VM_Name, $table1.VM_Cluster, $table1.VM_Zone, $table2.vFiler_IP, $table2.vFiler_Zone FROM $table1 join $table2  WHERE $table1.VM_Name = $table2.VM_Name";

有了这个，我的输出是：

[
  ["VM1", " Cluster4", "Zone3", " 10.10.10.10", "Zone5"],
  ["VM2", " Cluster3", "Zone4", " 10.10.10.11", "Zone8"],
  ["VM3", " Cluster2", "Zone1", " 10.10.10.12", "Zone8"],
  ["VM4", " Cluster1", "Zone2", " 10.10.10.13", "Zone8"],
]

<强>更新：如果我在用错字发布时使用use strict运行代码，我会得到：

Global symbol "$tabel1" requires explicit package name at test.pl line 3726.

如果我没有严格地运行它，我会收到一堆错误：

Bad table or column name: '.VM_Zone' has chars not alphanumeric or underscore! at C:/Perl/site/lib/SQL/Statement.pm line 88
DBD::CSV::db selectall_arrayref failed: Bad table or column name: '.VM_Zone' has chars not alphanumeric or underscore! at C:/Perl/site/lib/SQL/Statement.pm line 88
 [for Statement "SELECT file1.VM_Name, file1.VM_Cluster, .VM_Zone, file2.vFiler_IP, file2.vFiler_Zone FROM file1 join file2  WHERE file1.VM_Name = file2.VM_Name"] at test.pl line 3727.
DBD::CSV::db selectall_arrayref failed: Bad table or column name: '.VM_Zone' has chars not alphanumeric or underscore! at C:/Perl/site/lib/SQL/Statement.pm line 88
 [for Statement "SELECT file1.VM_Name, file1.VM_Cluster, .VM_Zone, file2.vFiler_IP, file2.vFiler_Zone FROM file1 join file2  WHERE file1.VM_Name = file2.VM_Name"] at test.pl line 3727.

您发布的内容与实际代码之间是否存在任何差异？你重新打字了吗？即使没有strict，也无法编译。它甚至无法输出[]，因为它在print语句之前消失。

如何将Perl中的2个CSV文件与DBI和DBD :: CSV合并？

2 个答案: