我想一条语句把老公和老婆的年龄一起读出来，我的想像中，SQL的输出应该如下：
c.husband |h.age |c.wife |w.age |
================================================
James |30 |Mary |22 |
Roger |24 |Lily |26 |
================================================
下面是可用的测试代码：（附件里面有测试文件，放到和脚本一起的目录应该就可以用)
#!/usr/bin/perl -w
use strict;
use DBI;
my $dbh = DBI->connect ("dbi:CSV:", "", "", {
f_ext => ".csv",
csv_null => 1,
FetchHashKeyName => 'NAME_lc',
});
my $query = "select c.husband,h.age,c.wife,w.age from couple c, people h,
people w where c.husband = h.name and c.wife = w.name";
#my $query = "select c.husband,h.age from couple c, people h where c.husband =
h.name ";
my $sth = $dbh->prepare ($query);
$sth->execute ();
while (my $row = $sth->fetchrow_hashref) {
foreach my $col ( keys %$row ) {
print $col,"=",$row->{$col},"\t" if defined $row->{$col};
}
print "done\n\n";
}
$sth->finish ();
________________________________
From: [email protected] [mailto:[email protected]] On
Behalf Of cnhack TNT
Sent: 2010年11月17日 9:41
To: [email protected]
Subject: Re: [PerlChina] CSV的SQL语句中一张表不能出现两次
为啥要 “people h, people w” ？
2010/11/17 ZHANG Jiaqiang A <[email protected]>
大家好，
有一张表，我需要多次关联，设了不同的别名，但是执行SQL的时候报错，大家有用过DBD-CSV的高手，帮我看看这是DBD
CSV的限制还是SQL写的不对
SQL语句:
select c.husband,h.age,c.wife,w.age from couple c, people h,
people w where c.husband = h.name and c.wife = w.name;
报错信息：
DBD::CSV::st execute failed: Error 2012 while reading file
D:\Perl\people.csv: E
OF - End of data in parsing input stream at
C:/strawberry/perl/site/lib/SQL/Stat
ement.pm line 813
[for Statement "select c.husband,h.age,c.wife,w.age from
couple c, people h, pe
ople w where c.husband = h.name and c.wife = w.name"] at csv.pl
line 99.
以下SQL语句都可以正常执行:
select * from couple;
husband |wife |
========================
James |Mary |
Roger |Lily |
========================
Return 2 columns and 2 lines
select * from people;
name |age |
========================
Mary |22 |
Lily |26 |
Roger |24 |
James |30 |
========================
Return 2 columns and 4 lines
select c.husband,h.age from couple c, people h where
c.husband = h.name;
c.husband |h.age |
========================
James |30 |
Roger |24 |
========================
Return 2 columns and 2 lines
select c.wife,w.age from couple c, people w where
c.wife = w.name;
c.wife |w.age |
========================
Mary |22 |
Lily |26 |
========================
Return 2 columns and 2 lines
祝好
家强
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people.csv
Description: people.csv
couple.csv
Description: couple.csv
