mongodb aggregate group if
If you specify an _id value of null, or any other constant value, the $group stage calculates accumulated values for all the input documents as a whole. ,If you place a $match at the very beginning of a pipeline, the query can take ... the results to the $group pipeline operator to compute a count of the documents:.
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 mongodb aggregate group if 相關參考資料
$cond (aggregation) — MongoDB Manual
$cond requires all three arguments ( if-then-else ) for either syntax. If the <boolean-expression> evaluates to true , then $cond evaluates and returns the value of ... https://docs.mongodb.com $group (aggregation) — MongoDB Manual
If you specify an _id value of null, or any other constant value, the $group stage calculates accumulated values for all the input documents as a whole. https://docs.mongodb.com $match (aggregation) — MongoDB Manual
If you place a $match at the very beginning of a pipeline, the query can take ... the results to the $group pipeline operator to compute a count of the documents:. https://docs.mongodb.com Group By Condition in MongoDB - Stack Overflow
The use of the $cond operator here determines whether the "status" is actually a defect or not and the result is a conditional $sum where only the "defect" values ... https://stackoverflow.com Mongo query aggregate with a conditional group and another ...
2019年1月3日 — You can follow below syntax to add another field in $group expression db.logs.aggregate([ "$match": "DateTime": "$gte": ninetyDays } ... https://stackoverflow.com MongoDB - How to Group By with Condition - Stack Overflow
2014年4月5日 — If you used the same names, the aggregation engine considers those fields to already be in the result document and leaves them at the top of the ... https://stackoverflow.com MongoDb Aggregate group and sort applications - Stack ...
2018年12月7日 — See if the below find & sort operation works with your real data. collection.find(}, _id : 0}).sort(appId:1, time:-1}). If this is a huge collection and ... https://stackoverflow.com MongoDB group aggregation with conditions - Stack Overflow
2017年4月26日 — If you have trouble with aggregation, since it is an array of operations, which are creating a pipeline, it is better to test each operation by itself, just ... https://stackoverflow.com MongoDB Group by Multiple Fields Using Aggregation Function
2019年7月7日 — If you do not use the GROUP BY clause, some aggregate functions in the SELECT list can only be used with other aggregate functions. That's ... https://kb.objectrocket.com MongoDB query with conditional group by statement - Stack ...
2015年1月28日 — Unwind the source field to list it as a field and not an array. (optional). Code: db.customer.aggregate([ $group: "_id": ... https://stackoverflow.com |