mongodb aggregate distinct
Groups input documents by the specified _id expression and for each distinct grouping, outputs a document. The _id field of each output document contains the ... ,2018年3月19日 — You can use $addToSet to group unique values in one document and then $unwind to get back multiple docs: db.ign.aggregate([ $group: ... ,If your results exceed the maximum BSON size, use the aggregation pipeline to retrieve distinct values using the $group operator, as described in Retrieve ... ,If your results exceed the maximum BSON size, use the aggregation pipeline to retrieve distinct values using the $group operator, as described in Retrieve Distinct Values with the Aggregation Pipeline. MongoDB also provides the shell wrapper method db. co,2014年3月30日 — Distinct is a type of grouping indeed but the output equivalent of that type of query is this: db.collection.aggregate([ "$group": "_id": "sid": ... ,Since you are willing to group also by DOB , you shuld include it in the _id of your group , like this: db.ped.aggregate([ $match:"DOB-Year":2014} }, $group: ... ,I was able to solve it based on a similar question: MongoDB : Aggregation framework : Get last dated document per grouping ID. My solution looks like this: ,2016年2月4日 — Distinct and the aggregation framework are not inter-operable. Instead you just want: db.zips.aggregate([ $group:_id:city:'$city', state:'$state'}, ... ,2017年7月24日 — MongoDB provides the aggregate() method in the format of db.collection.aggregate(). Aggregation operators like group, count, sum, or max ... ,You need to aggregate as below: Group by z and accumulate all the values of v using the $addToSet operator, to maintain unique lists of v , per group. Project ...
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 mongodb aggregate distinct 相關參考資料
$group (aggregation) — MongoDB Manual
Groups input documents by the specified _id expression and for each distinct grouping, outputs a document. The _id field of each output document contains the ... https://docs.mongodb.com Aggregate distinct values in MongoDB - Stack Overflow
2018年3月19日 — You can use $addToSet to group unique values in one document and then $unwind to get back multiple docs: db.ign.aggregate([ $group: ... https://stackoverflow.com db.collection.distinct() — MongoDB Manual
If your results exceed the maximum BSON size, use the aggregation pipeline to retrieve distinct values using the $group operator, as described in Retrieve ... https://docs.mongodb.com distinct — MongoDB Manual
If your results exceed the maximum BSON size, use the aggregation pipeline to retrieve distinct values using the $group operator, as described in Retrieve Distinct Values with the Aggregation Pipeline... https://docs.mongodb.com How to do distinct and group in MongoDB Aggregation ...
2014年3月30日 — Distinct is a type of grouping indeed but the output equivalent of that type of query is this: db.collection.aggregate([ "$group": "_id": "sid": ...... https://stackoverflow.com Mongodb aggregate with distinct - Stack Overflow
Since you are willing to group also by DOB , you shuld include it in the _id of your group , like this: db.ped.aggregate([ $match:"DOB-Year":2014} }, $group: ... https://stackoverflow.com MongoDB aggregation for distinct values - Stack Overflow
I was able to solve it based on a similar question: MongoDB : Aggregation framework : Get last dated document per grouping ID. My solution looks like this: https://stackoverflow.com MongoDB distinct aggregation - Stack Overflow
2016年2月4日 — Distinct and the aggregation framework are not inter-operable. Instead you just want: db.zips.aggregate([ $group:_id:city:'$city', state:'$state'}, ... https://stackoverflow.com MongoDB Query Language Part 2 – Count, Distinct, Group ...
2017年7月24日 — MongoDB provides the aggregate() method in the format of db.collection.aggregate(). Aggregation operators like group, count, sum, or max ... https://nisorness.com select distinct column count in Aggregation query in mongodb ...
You need to aggregate as below: Group by z and accumulate all the values of v using the $addToSet operator, to maintain unique lists of v , per group. Project ... https://stackoverflow.com |