#!/usr/bin/perl
use DBI;
my $dbfile = 'test.db';      # your database file

my $need2create = ! -f $dbfile;
my $dbh = DBI->connect(          # connect to your database, create if
+ needed
    "dbi:SQLite:dbname=$dbfile", # DSN: dbi, driver, database file
    "sq",                          # no user
    "lite",                          # no password
    { RaiseError => 1 },         # complain if something goes wrong
) or die $DBI::errstr;

my $table = 'test';
my @rows  = qw(id hobby email);

if($need2create){
    print "Creating $dbfile -> $table \n";
    $dbh->do("create table $table (".join(',',@rows).')')  or die $DBI
+::errstr;
    my @DATA = ('1|chess|camelot@aorta.com','2|math|dude@oops.no','3|m
+ath|foo@bar.com');
    for my $data (@DATA){
        $str ="insert into '$table' ('".join("','",@rows)."')"." value
+s ('".join("','",split(/\|/,$data))."')";
        print $str ."\n";
        $dbh->do($str)  or die $DBI::errstr;
    }
 }
 

$sql ="select * from $table";
my $sth = $dbh->prepare($sql);
$sth->execute(); 
my @SENDTO;
while (my @row = $sth->fetchrow_array) { # retrieve one row
    if($row[1]=~/math/i){
        print "emailing $row[2]\n";
        push(@SENDTO, $row[2]);
        # print "". join(", ", @row), "\n";
    }
}

for my $who (@SENDTO){
    $log = "I have emailed $who\n";
    print $log;
    &log_it;
}
[download]

Prints:

emailing dude@oops.no
emailing foo@bar.com
I have emailed dude@oops.no
I have emailed foo@bar.com
[download]

Alternative is that you concatenate your string with newlines, thus:

my $SENDTO = ""; # start with empty string
while (my @row = $sth->fetchrow_array) { # retrieve one row
    if($row[1]=~/math/i){
        $SENDTO .= "emailing $row[2]\n";
        push(@SENDTO, $row[2]);
    }
}

$log = $SENDTO;
&log_it;
[download]