perl 无法打印所需的输出

Question

您好，我正在编写一个 perl 脚本以使用 SQL Plus 连接到数据库，但是当我查询数据时，它没有显示正确的输出，有人可以解释一下吗？

$ perl test.pl -u user -p paswd -d database

while ($ARGV[0] =~ /^-/)
{
        $opt = shift;
        $dbuser = shift if ($opt eq "-u");
        $dbpasswd = shift if ($opt eq "-p");
        $db = shift if ($opt eq "-d");
}
$output=`echo "select sysdate from dual"  | sqlplus  $dbuser\/$dbpasswd\@$db`;
print $output;

输出屏幕：我希望输出为 sysdate。

SQL*Plus: Release 11.2.0.3.0 Production on Mon Feb 25 13:13:38 2019

Copyright (c) 1982, 2011, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> SQL>   2  Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

Answer 1

我认为缺少 ;

$output=`echo "select sysdate from dual;"  | sqlplus  $dbuser\/$dbpasswd\@$db`;

Answer 2

Sqlplus 需要许多设置才能使用。我建议：

$output=`( echo "set heading off" ; echo "set feedback off" ; echo "set newpage none" ; echo "set pagesize 0" ; echo "select sysdate from dual;" )  | sqlplus -s $dbuser\/$dbpasswd\@$db`;

别忘了咬住结果：

chomp $output

perl 无法打印所需的输出

perl not able print desired output

perl

sqlplus