thinkphp5---join聯合查詢

使用thinkphp3.2進行聯合查詢，join聯合查詢：

$list = M('document as d')
->join('tp_admin_column as c on d.cid = c.id')
// ->field('d.id,d.cid,d.title,d.url,d.state,d.addtime,d.arc_sort')
->limit(2)
->select();