SELECT DISTINCT是否可以与Perl的DBD :: CSV一起使用? [英] Does SELECT DISTINCT work with Perl's DBD::CSV?
问题描述
我在网上找到了一个SELECT示例. 当我在脚本中尝试时，出现以下错误消息:
I found a SELECT-example on the web. When I try it in my script I get this error-message:
Specifying DISTINCT when using aggregate functions isn't reasonable - ignored. at /usr/lib/perl5/site_perl/5.10.0/SQL/Parser.pm line 496.
#!/usr/bin/perl
use warnings;
use strict;
use DBI;
my $dbh = DBI->connect( "DBI:CSV:", undef, undef, { RaiseError => 1, AutoCommit => 1 } );
my $table = 'artikel';
my $array_ref = [ [ 'a_nr', 'a_name', 'a_preis' ],
[ 12, 'Oberhemd', 39.80, ],
[ 22, 'Mantel', 360.00, ],
[ 11, 'Oberhemd', 44.20, ],
[ 13, 'Hose', 119.50, ],
];
$dbh->do( "CREATE TEMP TABLE $table AS IMPORT(?)", {}, $array_ref );
my $sth = $dbh->prepare( "SELECT DISTINCT a_name FROM $table" );
$sth->execute();
$sth->dump_results();
$dbh->disconnect();
SELECT DISTINCT是否不能与DBD :: CSV一起使用，或者我的脚本有问题吗?
Does SELECT DISTINCT not work with DBD::CSV or is something wrong with my script?
输出是
'Oberhemd'
'Mantel'
'Oberhemd'
'Hose'
4 rows
'Oberhemd'
'Mantel'
'Oberhemd'
'Hose'
4 rows
我认为应该是
'Oberhemd'
'Mantel'
'Hose'
3 rows
'Oberhemd'
'Mantel'
'Hose'
3 rows
已安装的版本:
Perl : 5.010000 (x86_64-linux-thread-multi)
OS : linux (2.6.31)
DBI : 1.609
DBD::Sponge : 12.010002
DBD::SQLite : 1.25
DBD::Proxy : 0.2004
DBD::Gofer : 0.011565
DBD::File : 0.37
DBD::ExampleP : 12.010007
DBD::DBM : 0.03
DBD::CSV : 0.26
Perl : 5.010000 (x86_64-linux-thread-multi)
OS : linux (2.6.31)
DBI : 1.609
DBD::Sponge : 12.010002
DBD::SQLite : 1.25
DBD::Proxy : 0.2004
DBD::Gofer : 0.011565
DBD::File : 0.37
DBD::ExampleP : 12.010007
DBD::DBM : 0.03
DBD::CSV : 0.26
推荐答案
这是一个易于复制的错误. SELECT data_display_mask FROM test.csv返回200多行. SELECT DISTINCT data_display_mask FROM test.csv返回警告消息和相同的200行.
Hi This is an easily reproducable bug. SELECT data_display_mask FROM test.csv returns 200 plus rows. SELECT DISTINCT data_display_mask FROM test.csv returns the warning message and same 200 rows.
如果我执行awk，将-u排序为唯一(行的值)，我得到36个值，这是我期望的值.
If i do an awk, sort -u for unique ( values of the row ) I get 36 values, which is what I would expect.
肯定是代码中的错误.
-Kanwar
perl -V 我的perl5(修订版5版本10子版本0)的配置摘要: 平台: osname = linux，osvers = 2.2.24-6.2.3，archname = i686-linux-thread-multi
perl -V Summary of my perl5 (revision 5 version 10 subversion 0) configuration: Platform: osname=linux, osvers=2.2.24-6.2.3, archname=i686-linux-thread-multi
DBD :: CSV 0.26 SQL ::解析器1.23 DBI 1.609
DBD::CSV 0.26 SQL::Parser 1.23 DBI 1.609
示例:
在使用聚合函数时指定DISTINCT是不合理的-会被忽略.在/opt/perl2exe/perl5/lib/site_perl/5.10.0/SQL/Parser.pm行496中. 87060 87060 87060 87060
Specifying DISTINCT when using aggregate functions isn't reasonable - ignored. at /opt/perl2exe/perl5/lib/site_perl/5.10.0/SQL/Parser.pm line 496. 87060 87060 87060 87060
使用的SQL是来自test.csv的SELECT DISTINCT entry_id
SQL used is SELECT DISTINCT entry_id FROM test.csv
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