如何在sqlite中使用限制

Question

get '/' => sub { 
     my $db = connect_db(); 
     my $sql = 'select id, title, text from entries order by id desc limit 3 offset 4'; 
     my $sth = $db->prepare($sql) or die $db->errstr; 
     $sth->execute or die $sth->errstr; 
     template 'show_entries.tt', { 
       'msg' => get_flash(), 
       'add_entry_url' => uri_for('/add'), 
       'entries' => $sth->fetchall_hashref('id'), 
     }; 
}; 

我想在主頁面上顯示3個主題，但由於某種原因顯示全部。我做錯了什麼？

Answer 1

對我的作品

$ perl -E' 
    use DBI; 
    my $dbh = DBI->connect("dbi:SQLite:", undef, undef, 
     { PrintError => 0, RaiseError => 1, AutoCommit => 1 }); 

    $dbh->do("CREATE TEMP TABLE MyTable (id INT)"); 
    $dbh->do("INSERT INTO MyTable VALUES (?)", undef, $_) for 1..9; 

    my $sql = "SELECT * FROM MyTable LIMIT 3 OFFSET 4"; 
    my $sth = $dbh->prepare($sql); 
    $sth->execute(); 
    say for keys %{ $sth->fetchall_hashref("id") }; 
' 
5 
6 
7 

，或者在命令行客戶端

$ sqlite3 
SQLite version 3.3.6 
Enter ".help" for instructions 
sqlite> CREATE TEMP TABLE MyTable (id INT); 
sqlite> INSERT INTO MyTable VALUES (1); 
sqlite> INSERT INTO MyTable VALUES (2); 
sqlite> INSERT INTO MyTable VALUES (3); 
sqlite> INSERT INTO MyTable VALUES (4); 
sqlite> INSERT INTO MyTable VALUES (5); 
sqlite> INSERT INTO MyTable VALUES (6); 
sqlite> INSERT INTO MyTable VALUES (7); 
sqlite> INSERT INTO MyTable VALUES (8); 
sqlite> INSERT INTO MyTable VALUES (9); 
sqlite> SELECT * FROM MyTable LIMIT 3 OFFSET 4; 
5 
6 
7 
sqlite> .q 

版本：

$ perl -MDBI -E' 
    my $dbh = DBI->connect("dbi:SQLite:", undef, undef); 
    say for 
     $DBD::SQLite::VERSION, 
     $dbh->{sqlite_version} 
' 
1.40 
3.7.17