Find Command Projection Operators查找命令投影运算符
The following pages describe specialized operators that are only available in find command projections. 以下页面描述了仅在find命令投影中可用的专用运算符。In addition to these specialized operators, find command projections can also contain non-specialized expressions.除了这些专用运算符外，find命令投影还可以包含非专用表达式。
Name名称 | Description描述 |
|---|
$ | Projects the first element in an array that matches the query condition.投影数组中与查询条件匹配的第一个元素。 |
$elemMatch | Projects the first element in an array that matches the specified $elemMatch condition.投影数组中与指定的$elemMatch条件匹配的第一个元素。 |
$meta | Projects the available per-document metadata.投影每个文档的可用元数据。 |
$slice | Limits the number of elements projected from an array. Supports skip and limit slices.限制从数组投影的元素数量。支持跳过和限制分片。 |
Note
View Support查看支持
find() operations on views do not support any of the preceding projection operators.find()操作不支持前面的任何投影运算符。