1. 原生查询：

$Model = new \Think\Model();

$sql='select a.*,b.*,c.* from cgw_picture as a,cgw_terms as b,cgw_users as c where a.parent_id=b.term_id and a.post_author=c.id order by a.post_modified desc limit '.($nowpage-1)*$limits.','.$limits;

$lists=$Model->query($sql);

  2.左查询

$model=M('picture');

            $lists=$model->alias('p')->join('LEFT JOIN cgw_terms t on p.parent_id=t.term_id')->join('LEFT JOIN cgw_users u on p.post_author=u.id')->field('p.*,t.name,u.user_login')->order('p.post_modified desc')->page($nowpage, $limits)->select();

3.三表左连接查询

SELECT a.*,b.`price`,b.`total`,b.`billing_method` FROM `product` a

LEFT JOIN `product_billing` b ON a.`id` = b.`product_id`LEFT JOIN `user` c ON a.`user_id`= c.`id` WHERE 1=1 AND c.`type_id`='ORG' GROUP BY a.`id` LIMIT 0,15

3.两表联查统计

SELECT COUNT(*) FROM `product` a LEFT JOIN `user` b

ON a.`user_id`=b.`id` WHERE 1=1  AND a.`area_id` = 0 AND a.`product_class_id` = 1 AND a.`product_base_id` = 1 AND b.`type_id`='ORG'