Mongo相当于SQL的SELECT DISTINCT？

Question

按标题，这将是PHP蒙戈相当于像这样的SQL：

SELECT DISTINCT(field) FROM table WHERE someCondition = 1 

我读过看着this table，但我看不出如何db.users.distinct('last_name')映射到PHP。

Answer 1

只需发出command并设置密钥distinct。

看看下面的例子从文档：

查找所有不同值的关键。

<?php 

$people = $db->people; 

$people->insert(array("name" => "Joe", "age" => 4)); 
$people->insert(array("name" => "Sally", "age" => 22)); 
$people->insert(array("name" => "Dave", "age" => 22)); 
$people->insert(array("name" => "Molly", "age" => 87)); 

$ages = $db->command(array("distinct" => "people", "key" => "age")); 

foreach ($ages['values'] as $age) { 
    echo "$age\n"; 
} 

?> 

上例的输出类似于：

4 
22 
87 

Answer 2

如果您需要添加WHERE子句，请使用以下语法：

$ages = $db->command(array(
    "distinct" => "people", 
    "key" => "age", 
    "query" => array("someField" => "someValue")));