使用聚合管道,我尝试将嵌入的文档投影到根级别的,而不是单独投影每个字段。
例如,我希望将name
从这个集合投影到根级别:
[
{
_id: "1",
name: {
firstName: "John",
lastname: "Peters"
}
},
{
_id: "2",
name: {
firstName: "Mary",
lastname: "Jones"
}
}
]
这就是我要找的:
[
{
firstName: "John",
lastname: "Peters"
},
{
firstName: "Mary",
lastname: "Jones"
}
]
有没有办法在不单独投影每个字段的情况下做到这一点?我不想这样做:
db.collection.aggregate(
[
{
$project : {
"_id" : 0,
"firstName" : "$name.firstName",
"lastName" : "$name.lastName"
}
}
]
https://stackoverflow.com/questions/35183432
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