【三十三】thinkphp之SQL查询语句（全）

一：字符串条件查询

        //直接实例化Model
        $user=M('user1');
        var_dump($user->where ('id=1 OR age=55')->select());

最终生成的sql语句为：SELECT * FROM `user1` WHERE ( id=1 OR age=55 )

PS:where 查询方法里面只要包含条件即可，多个条件加上 AND 等连接符即可

二：使用索引数组作为查询条件

        $user=M('user1');
        $condition['age']='55';
        $condition['name']='zs';
        // 索引数组查询的默认逻辑关系是 AND，如果想改变为 OR，可以使用_logic 定义查询逻辑
        $condition['_logic'] = 'OR';
        var_dump($user->where($condition)->select());

最终生成的sql语句为：SELECT * FROM `user1` WHERE `id` = ‘1’ AND `name` = 'zs'

三：使用对象方式查询

<?php
namespace Home\Controller;
use Think\Controller;
use Think\stdClass;
class EleController extends Controller
{
        $user=M('user1');
        $condition=new \stdClass;
        $condition->id = '1';
        var_dump($user->where($condition)->select());
}

最终生成的sql语句为：SELECT * FROM `user1` WHERE `id` = ‘1’

四：表达式查询

查询表达式格式：$map['字段名'] = array('表达式','查询条件');

        $user=M('user1');
        $map['age'] = array('eq', 55); //where 为 age=55
        var_dump($user->where($map)->select());        

五：快捷查询

        //使用相同查询条件
        $user = M('user1');
        $map['name|email'] = 'a'; //'|'换成'&'变成AND
        var_dump($user->where($map)->select());
        // 不同字段不同查询条件
        //使用不同查询条件
        $user = M('user1');
        $map['name&email'] =array('a','test@qq.com','_multi'=>true);
        var_dump($user->where($map)->select());    

第一条查询的结果：SELECT * FROM `user1` WHERE ( `name` = 'a' OR `email` = 'a' )

第二条查询的结果：SELECT * FROM `user1` WHERE ( (`name` = 'a') AND (`email` = 'test@qq.com') )

六：区间查询

　　　　// 区间查询
        $user = M('user1');
        $map['id'] = array(array('gt', 1), array('lt', 4));
        var_dump($user->where($map)->select());
        //第三个参数设置逻辑OR
        $user = M('User1');
        $map['id'] = array(array('gt', 1), array('lt', 4), 'OR');
        var_dump($user->where($map)->select()
    }

七：组合查询

组合查询是基于索引数组查询方式的一个扩展性查询，添加了字符串查询(_string)、复合查询(_complex)、请求字符串查询(_query)，由于采用的是索引数组，重复的会被覆盖。

        //字符串查询(_string)
        $user = M('user1');
        $map['name'] = array('eq', 'zs');
        $map['_string'] ='age="30" AND email="zs@qq.com"';
        var_dump($user->where($map)->select());
        //请求字符串查询(_query)
        $user = M('user1');
        $map['id'] = array('eq', "1");
        $map['_query'] ='name=zs&email=zs@qq.com&_logic=OR';
        var_dump($user->where($map)->select());
        //复合查询(_complex)
        $user = M('user1');
        $where['name'] = array('like', 'z');
        $where['id'] = 1;
        $where['_logic'] = 'OR';
        $map['_complex'] = $where;
        $map['id'] = 3;
        $map['_logic'] = 'OR';
        var_dump($user->where($map)->select());

第一条查询语句：SELECT * FROM `user1` WHERE `name` = 'zs' AND ( age="30" AND email="zs@qq.com" )

第二条查询语句：SELECT * FROM `user1` WHERE `name` = 'zs' AND ( age="30" AND email="zs@qq.com" ) AND ( `name` = 'zs' OR `email` = 'zs@qq.com' )

第三条查询语句：SELECT * FROM `user1` WHERE `name` = 'zs' OR ( age="30" AND email="zs@qq.com" ) OR ( `name` = 'zs' OR `email` = 'zs@qq.com' ) OR ( `name` LIKE 'z' OR `id` = 1 )

八：统计查询

        //数据总条数
        //SHOW COLUMNS FROM `user1`
        $user = M('user1');
        var_dump($user->count());
        //字段总条数，遇到NULL不统计
        //SELECT COUNT(*) AS tp_count FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->count('email'));
        //最大值
        //SELECT MAX(id) AS tp_max FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->max('id'));
        //最小值
        //SELECT MIN(id) AS tp_min FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->min('id'));
        //平均值
        //SELECT AVG(id) AS tp_avg FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->avg('id'));
        //求总和
        //SELECT SUM(id) AS tp_sum FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->sum('id'));

九：动态查询

        // 1.getBy 动态查询
        //查找email=xiaoin@163.com的数据
        //SELECT * FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->getByemail('zs@qq.com'));
        // 2.getFieldBy 动态查询
        //通过user得到相对应id值
        //SELECT `id` FROM `user1` LIMIT 1
        $user = M('user1');
        var_dump($user->getFieldByUser('ls', 'id'));

十：SQL查询

　　　　　// 1.query 读取
        //查询结果集，如果采用分布式读写分离，则始终在读服务器执行
        //SELECT * FROM user1
        $user = M('user1');
        var_dump($user->query('SELECT * FROM user1'));
        // 2.execute写入
        //更新和写入，如果采用分布式读写分离，则始终在写服务器执行
        //UPDATE user1 set name="xuexi" WHERE id="1";
        $user = M('user1');
        var_dump($user->execute('UPDATE user1 set name="xuexi" WHERE
         id="1";'));

十一：连贯查询

通过连贯操作可以有效的提供数据存取的代码清晰度和开发效率，并且支持所有的 CURD 操作

        //连贯操作
        //PS：这里的 where、order 和 limit 方法都是连贯操作方法，所以它们都能返回$user本身，可以互换位置。而 select 方法不是连贯方法，需要放在最后，用以显示数据集。
        //SELECT * FROM `user1` WHERE ( id in (1,2,3,4) ) LIMIT 2
        $user=M('user1');
        var_dump($user->where('id in (1,2,3,4)')->limit(2)->select());
        //数组操作
        //SELECT * FROM `user1` WHERE id in (1,2,3,4) LIMIT 2
        $user = M('user1');
        var_dump($user->select(array('where'=>'id in (1,2,3,4)', 'limit'=>'2',
        )));
        // CURD处理
        // SELECT * FROM `user1` WHERE ( id=1 ) LIMIT 1
        // DELETE FROM `user1` WHERE ( id=2 )
        $user = M('user1');
        var_dump($user->where('id=1')->find());
        var_dump($user->where('id=2')->delete());

1.where(支持字符串条件、数组条件（推荐用法）和多次调用。)

        //字符串方式
        //SELECT * FROM `user1` WHERE ( id=6 )
        var_dump($user->where('id=6')->select());

        //索引数组方式
        // SELECT * FROM `user1` WHERE `id` = 6
        $map['id']=6;
        var_dump($user->where($map)->select());

        //多次调用方式
        SELECT * FROM `user1` WHERE `id` = 6 AND ( name="test" )
        $map['id']=array('eq',6);
        var_dump($user->where($map)->where('name="test"')->select());

2.order 用于对结果集排序

    // 倒序
        // SELECT * FROM `user1` ORDER BY id desc
        var_dump($user->order('id desc')->select());

        // 第二排序
        // SELECT * FROM `user1` ORDER BY id desc,age desc
        var_dump($user->order('id desc,age desc')->select());

        //数组形式，防止字段和mysql关键字冲突
        // SELECT * FROM `user1` ORDER BY `id` DESC,`email` DESC
        $map['id']=1;
        var_dump($user->order(array('id'=>'DESC','email'=>'DESC'))->select());

3.feild（feild 方法可以返回或操作字段，可以用于查询和写入操作。）

　　　　// 只显示id和name两个字段
      // SELECT `id`,`name` FROM `user1`
        var_dump($user->field('id,name')->select());

      //使用SQL函数和别名
      // SELECT SUM(id) as count,`name` FROM `user1`
      var_dump($user->field('SUM(id) as count,name')->select());

      // 使用数组参数结合SQL函数
      // SELECT `id`,LEFT(name,1) AS `left_user` FROM `user1`
      var_dump($user->field(array('id','LEFT(name,1)'=>'left_user'))->select());

      //获取所有字段
      // SELECT * FROM `user1`
      var_dump($user->field()->select());

      //用于写入
      $user->field('name,email')->create();

4.limit（主要用于指定查询和操作的数量）

      //限制结果集数量
      // SELECT * FROM `user1` LIMIT 2
      var_dump($user->limit(2)->select());

      //分页查询
      // SELECT * FROM `user1` LIMIT 1,2
      var_dump($user->limit(1,2)->select());

5.page（page 方法完全用于分页查询）

      //page分页
      // SELECT * FROM `user1` LIMIT 3,3
      var_dump($user->page(2,3)->select());

6.table（用于数据表操作，主要是切换数据表或多表操作）

      //切换数据表
      // SELECT * FROM `test_user`
      var_dump($user->table('test_user')->select());

7.alias （用于设置数据表别名）

      // 设置别名
      // SELECT * FROM user1 a
      var_dump($user->alias('a')->select());

8.group（用于对结合函数统计的结果集分组）

　　　　// 分组统计
      // SELECT `name`,max(id) FROM `user1` GROUP BY id
      var_dump($user->field('name,max(id)')->group('id')->select());

9.having（用于配合 group 方法完成从分组的结果中再筛选数据）

      //分组统计结合having
      // SELECT `user`,max(id) FROM `user1` GROUP BY id HAVING id>2
      var_dump($user->field('user,max(id)')->group('id')->having('id>2')->select());

10.comment （用于对 SQL 语句进行注释）

      //SQL注释
      // SELECT * FROM `user1` /* test */
      var_dump($user->comment('test')->select());

命名空间

命名范围其实就是将 SQL 语句封装在模型定义类里，而不在控制器里。

在Model下新建一个User1Model.class.php文件

<?php
namespace Home\Model;
use Think\Model;
class User1Model extends Model
{
    //定义属性
protected $_scope = array( //属性名必须是_scope
        'sql1'=>array(
        'where'=>array('id'=>1),
        ),
        'sql2'=>array(
        'order'=>'date DESC',
        'limit'=>2,
        ),
        'default'=>array(
        'where'=>array('id'=>2),
        ),
        );
}

命名范围支持的属性有：where、field、order、table、limit、page、having、group、lock、distinct、cache

在Controller目录下新建一个User1Controller.class.php文件

<?php
namespace Home\Controller;
use Think\Controller;
use Home\Model\User1Model;
class User1Controller extends Controller {
    public function model(){
        // ps：一定要填入表名，user1
        // 他会先去model文件夹找有没有user1model
        // 如果有就应用
        // 如果没有，会直接引用model基类
        $user=D('user1');
        // sql语句：SELECT * FROM `user1` WHERE `id` = 1
        var_dump($user->scope('sql1')->select());
    }
}