管道阶段规范对象必须仅包含一个带有php mongo聚合的字段 [英] A pipeline stage specification object must contain exactly one field with php mongo aggregate
问题描述
我正在尝试将aggregate与项目,匹配项和排序项一起使用,但出现了异常(MongoResultException
准确地说)
I am trying to use aggregate with with project, match and sort but i am getting an exception (MongoResultException
to be exact) saying
exception: A pipeline stage specification object must contain exactly one field.
当我不使用排序和限制,但为此需要它们时,它工作正常.我之所以不使用find()
的原因是因为我在某处读到它可以提高性能.
请帮助
It works fine when I did not use sort and limit but I need them for this. The reason I am not using find()
because I read somewhere that it can increase performance.
Please help
$query = array(.... //An actual query that works with find()
$collection = $this->db->CollectionName;
$project = array(
'$project' => array(
'Field1' => 1,
'Field2'=> 1,
'Field3'=> 1,
'Field4' => 1
)
);
$match = array( '$match'=>$query);
$sort = array('Field3' => -1, 'Field4'=>-1);
$limit = array('$limit' => 100);
$result = $collection->aggregate(array($match,$project,$sort,$limit));
return $result;
推荐答案
问题似乎出在您的$sort
作业上.你有
It looks like the problem is your $sort
assignment. You have
$sort = array('Field3' => -1, 'Field4'=>-1);
实际上并没有给出$sort
阶段规范.不应该是:
which doesn't actually give the $sort
stage specification. Shouldn't it be:
$sort = array('$sort' => array( 'Field3' => -1, 'Field4'=>-1 ) );
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