mongodb 分组查询 - 小蕊同学

数据的保存

include_once \'mDB.class.php\';
$m=new mDB();
$m->setDB(\'mydb\');
// $m->save(\'stu\',[\'dept\'=>\'财务\',\'name\'=>\'张三\',\'age\'=>73]);
// $m->save(\'stu\',[\'dept\'=>\'计算机\',\'name\'=>\'张四\',\'age\'=>53]);
// $m->save(\'stu\',[\'dept\'=>\'计算机\',\'name\'=>\'张五\',\'age\'=>23]);
// $m->save(\'stu\',[\'dept\'=>\'财务\',\'name\'=>\'张六\',\'age\'=>93]);
// $m->save(\'stu\',[\'dept\'=>\'计算机\',\'name\'=>\'张七\',\'age\'=>83]);
// $m->save(\'stu\',[\'dept\'=>\'法学\',\'name\'=>\'张八\',\'age\'=>53]);

查询出所有的专业

$db=$m->getMongoClient();
$d=$db->mydb;
$c=$d->stu;
// echo $c->find([\'dept\'=>\'计算机\'])->count();//返回计算机专业有几人
$currsor=$c->find([],[\'_id\'=>0,\'dept\'=>1]);
foreach ($currsor as $v){
    echo $v[\'dept\'].\'<br>\';
}

消除重复取出各个专业的名字distinct

$db=$m->getMongoClient();
$d=$db->mydb;
$c=$d->stu;
$depts=$c->distinct(\'dept\');
foreach ($depts as $v){
    echo $v.\'<br>\';
}

统计各个专业的人数

include_once \'mDB.class.php\';
$m=new mDB();
$m->setDB(\'mydb\');
$db=$m->getMongoClient();
$d=$db->mydb;
$c=$d->stu;
$depts=$c->distinct(\'dept\');
foreach ($depts as $v){
    echo $v;
    echo \'专业人数\'.$c->find([\'dept\'=>$v])->count();
    echo \'<hr>\';
}

分组查询的所有代码

<?php
header(\'content-type:text/html;charset=UTF-8\');
//无密码直接登录mongodb
$m = new MongoClient(\'mongodb://localhost:27017\');
$db = $m->selectDB(\'aaa\');
$c1 = $db->student;
//$c1->insert(array("category" => "计算机", "name" => "张在",\'age\'=>33));
//$c1->insert(array("category" => "计算机", "name" => "李四",\'age\'=>25));
//$c1->insert(array("category" => "英语", "name" => "赵六",\'age\'=>30));
//$c1->insert(array("category" => "英语", "name" => "赵七",\'age\'=>40));
//$c1->insert(array("category" => "会计", "name" => "李勇",\'age\'=>10));

//$keys = array("category" => 1);
//$initial = array("items" => array());
//$reduce = "function (obj, prev) { prev.items.push(obj);}";
//$reduce = "function (obj, prev) { prev.items.push(obj.name);}";
//$reduce = "function (obj, prev) { prev.items.push(obj.name+obj.age);}";
//$g = $c1->group($keys, $initial, $reduce);
//echo json_encode($g[\'retval\']);
//echo \'<pre>\';
//print_r($g);


//统计各专业人数
// $keys = array("category" => 1); //指定分类属性
// $initial = array("count" => 0);
// $reduce = "function (obj, prev) { prev.count++; }";
// $condition = array(\'condition\' => array());//条件
// $g = $c1->group($keys, $initial, $reduce, $condition);
// var_dump($g);

//统计年龄大于等于25岁的总人数
// $keys=[];
// $initial = [\'c\'=>0];
// $reduce = \'function(obj,prev){prev.c++;}\';
// $where = [\'condition\'=>[\'age\'=>[\'$gte\'=>25]]];
// $g = $c1->group($keys,$initial,$reduce,$where);
// var_dump($g);

//求出各专业学生年龄之和    select category,sum(age) from student group by category;
// $keys=[\'category\'=>1];
// $initial = [\'sum\'=>0];
// $reduce = "function(obj,prev){prev[\'sum\'] += obj.age; }";
// $g = $c1->group($keys,$initial,$reduce);
// var_dump($g);

//根据专业，来统计各专业的最大年龄
// $keys=[\'category\'=>1];
// $initial = [\'max\'=>0];
// $reduce = "function(obj,prev){if(obj.age>prev[\'max\']){prev[\'max\']=obj.age;} }";
// $g = $c1->group($keys,$initial,$reduce);
// var_dump($g);

//根据专业分组，求出每个专业的人数，平均年龄，年龄总各
$keys=[\'category\'=>1];
$initial = [\'sum\'=>0,\'count\'=>0,\'avg\'=>0];
$reduce = "function(obj,prev){prev[\'sum\'] += obj.age;prev[\'count\']++;prev[\'avg\']=prev[\'sum\']/prev[\'count\']}";
$g = $c1->group($keys,$initial,$reduce);
var_dump($g);
$m->close();

查询出所有的信息

include_once \'mDB.class.php\';
$m=new mDB();
$m->setDB(\'mydb\');
$db=$m->getMongoClient();
$d=$db->mydb;
$c=$d->stu;
$keys = ["dept" => 1]; //指定分类属性
$initial = array("count" => 0);
$reduce = "function (obj, prev) { prev.count++; }";
$condition = array(\'condition\' => array());//条件
$g = $c->group($keys, $initial, $reduce, $condition);
echo \'<pre>\';
var_dump($g);

统计出所有的信息

$reduce = "function (obj, prev) { prev.count++; }";此句为程序里面的死命令

<?php 
include_once \'mDB.class.php\';
$m=new mDB();
$m->setDB(\'mydb\');
$db=$m->getMongoClient();
$d=$db->mydb;
$c=$d->stu;
$keys = ["dept" => 1]; //指定分类属性
$initial = array("count" => 0);
$reduce = "function (obj, prev) { prev.count++; }";
$condition = array(\'condition\' => array());//条件
$g = $c->group($keys, $initial, $reduce, $condition);
echo \'<pre>\';
var_dump($g);
echo \'总人数\'.$g[\'count\'];
echo \'<br>总专业\'.$g[\'keys\'].\'个专业<br>\';
foreach ($g[\'retval\'] as $v){
    echo $v[\'dept\'].\'人数\'.$v[\'count\'].\'人\';
}

"function(obj,prev){

    prev[\'sum\'] += obj.age;

    prev[\'count\']++;

    prev[\'avg\']=prev[\'sum\']/prev[\'count\'];

   if(obj.age>prev[\'max\']){prev[\'max\']=obj.age;}

    if(obj.age<prev[\'min\']){prev[\'min\']=obj.age;}

}";  

求出平均分，最高分，最低分，各专业的总分

<?php 
include_once \'mDB.class.php\';
$m=new mDB();
$m->setDB(\'mydb\');
$db=$m->getMongoClient();
$d=$db->mydb;
$c=$d->stu;
//根据专业分组，求出每个专业的人数，平均年龄，年龄总各
$keys=[\'dept\'=>1];
$initial = [\'sum\'=>0,\'count\'=>0,\'avg\'=>0,\'max\'=>0,\'min\'=>100];
$reduce ="function(obj,prev){
    prev[\'sum\'] += obj.age;
    prev[\'count\']++;
    prev[\'avg\']=prev[\'sum\']/prev[\'count\'];
   if(obj.age>prev[\'max\']){prev[\'max\']=obj.age;}
    if(obj.age<prev[\'min\']){prev[\'min\']=obj.age;}
}";  
$g = $c->group($keys,$initial,$reduce);
echo \'<pre>\';
var_dump($g);
foreach ($g[\'retval\'] as $v){
echo  $v[\'dept\'].\'平均分\'.$v[\'avg\'].\'最高分\'.$v[\'max\'].\'最低分\'.$v[\'min\'].\'各专业总分为\'.$v[\'sum\'].\'<br>\';
}

来自为知笔记(Wiz)