您可以使用
$toObjectId
聚合实现此目的,该聚合仅将字符串ID转换为mongoose objectId
db.collection('article').aggregate([
{ "$lookup": {
"from": "comments",
"let": { "article_Id": "$_id" },
"pipeline": [
{ "addFields": { "articleId": { "$toObjectId": "$articleId" }}},
{ "$match": { "$expr": { "$eq": [ "$articleId", "$$article_Id" ] } } }
"as": "comments"
或者使用$toString聚合
db.collection('article').aggregate([
{ "addFields": { "article_id": { "$toString": "$_id" }}},
{ "$lookup": {
"from": "comments",
"localField": "article_id",
"foreignField": "articleId",
"as": "comments"
