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Homephp教程php手册ThinkPHP中limit()使用方法详解,thinkphplimit

ThinkPHP中limit()使用方法详解,thinkphplimit

本文介绍ThinkPHP的limit()方法的用法。limit方法可以用于对数据库操作的结果进行取指定范围的条数。即相当于是在mysql查询语句中的limit子句。

limit方法也是模型类的连贯操作方法之一,主要用于指定查询和操作的数量,特别在分页查询的时候使用较多。ThinkPHP的l

imit方法可以兼容所有的数据库驱动类的。

用法一、限制结果数量

例如获取满足要求的10个用户,如下调用即可:

 $User = M('User');
  $User->where('status=1')->field('id,name')->limit(10)->select();

limit方法也可以用于写操作,例如更新满足要求的3条数据:

  $User = M('User');
  $User->where('score=100')->limit(3)->save(array('level'=>'A'));

用法二、分页查询

用于文章分页查询是limit方法比较常用的场合,例如:

  $Article = M('Article');
  $Article->limit('10,25')->select();

表示查询文章数据,从第10行开始的25条数据(可能还取决于where条件和limit排序的影响 这个暂且不提)。

在3.1版本后,你也可以这样使用:

  $Article = M('Article');
  $Article->limit(10,25)->select();

对于大数据表,尽量使用limit限制查询结果,否则会导致很大的内存开销和性能问题。

关于ThinkPHP中limit()的使用方法就给大家介绍这么多,希望对您有所帮助,同时也非常感谢大家对帮客之家网站的支持!

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