aggregation with respect to one field except one value of that field-CodePudding

I am writing a query to do aggregation with respect to one field, however, I want to exclude this aggregation for one value of that field

let coAuthorCutThreshold =100

network.aggregate([
  { $group: { _id: '$title', title :{$ne: "class notes"}, count: { $sum: 1 } }} ,
  { $match: { count: { $gt: coAuthorCutThreshold } } },
  { $sort: { count: -1 } }
]).forEach(function (obj) {
  cutTitles.push(obj._id)
});

I want to do aggregation with respect to title but do to not want to do aggregation where the title is "class notes". I tried many command but did not work

I want to include all those values in cutTitles except where title is "class notes"

CodePudding user response：

Match in order to filter out the documents you don't want to group before the group stage.

let coAuthorCutThreshold = 100

network.aggregate([
  { $match: { title: { $ne: "class notes" }}},
  { $group: { _id: '$title', count: { $sum: 1 }}},
  { $match: { count: { $gt: coAuthorCutThreshold }}},
  { $sort: { count: -1 }}
]).forEach(function (obj) {
  cutTitles.push(obj._id)
});