perl - 打印 sql 行

Question

我想打印我的 perl 脚本的所有 sql 结果，我已经连接到数据库，我想显示我的 sql 查询的结果：

MySQL("SELECT * FROM test");

# define subroutine to submit MySQL command
 sub MySQL
 {   
     #Connect to the database.
     my $dbh = DBI->connect("DBI:mysql:database=database;host=ip",
     "login", 'password',
     {'RaiseError' => 1});

     my $query = $_[0];  #assign argument to string

     my $sth = $prepare($query);   #prepare query

     $sth->execute();   #execute query

     while (my @row = $sth->fetchrow_array)
        {
            print "@row\n";
        }
}

我有这个错误：

Global symbol "$prepare" requires explicit package name at test3.pl line 34.
syntax error at test3.pl line 34, near "$prepare("
Global symbol "$sth" requires explicit package name at test3.pl line 36.
Execution of test3.pl aborted due to compilation errors.

Answer 1

目前我手头没有可用的数据库。以下示例在理论上应该有效。我已经在 fetch_hashref 上替换了 fetch_array，输出将提供有关每一行的信息

ddddd column=value\tcolumn=value\t...

use strict;
use warnings;

my $query = qq(SELECT * FROM tb_test);

db_query($query);

sub db_query {
    my $query = shift;

    my $count = 1;

    my $dbh = DBI->connect(
                    "DBI:mysql:database=database;host=ip",
                    "login", 'password',
                    {'RaiseError' => 1}
              );

    my $sth = $dbh->prepare($query);

    $sth->execute();

    while ( my $row = $sth->fetchrow_hashref() ) {

            print "%5d ", $count++; # rows count

            while( my($k,$v) = each %$row ) { print "%s=%s\t",$k,$v; }

            print "\n"; # we done with current row
    }

    $sth->finish;
    $dbh->disconnect;
}

您需要查看 DBI 文档以全面了解其工作原理。

Answer 2

在您的上一篇文章中，以下评论中只有一个对 e 的引用

#INNER JOIN events e ON (e.objectid = t.triggerid)

可能最好使用语法INNER JOIN events as e ON (e.objectid = t.triggerid) -- 更具可读性

Answer 3

改变这一行：

my $sth = $prepare($query);

到

my $sth = $dbh->prepare($query);

不要忘记在 while 循环之后关闭 $sth 和 $dbh 句柄：

$sth->finish;
$dbh->disconnect;