Mongo remove document if all elements in array match condition

Question

Docs:

{
  _id: 1,
  items: [{thing: 5}, {thing: 7}]
}
{
  _id: 2,
  items: [{thing: 5}, {thing: 11}]
}

I would like to remove all docs from the collection above if all elements in array have "thing" < 10. IE for that case doc 1 should be removed, doc 2 should remain.

Is it possible with a query to find only docs where all elements in the array match with a $lt query?

I tried this:

db.mycollection.remove({items: {$all: [{$elemMatch: {thing: {$lt: 11}}}]}})

However that will remove all docs if any of the elements in the array match the condition.

https://stackoverflow.com/questions/16959099/how-to-remove-array-element-in-mongodb — Alok Deshwal, Dec 10 '20 at 20:07
@AlokDeshwal not the same question. I want to remove the entire document if all elements in array match, not just pull matching elements from document. — lostintranslation, Dec 10 '20 at 20:08

Danny Varod · Accepted Answer · 2020-12-10T20:49:34.750

1

Use double negative (De-Morgan law):

{items: {$not: {$elemMatch: {thing: {$gte: 11}}}}}

edited Dec 10 '20 at 20:49

answered Dec 10 '20 at 18:52

Danny Varod

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Mongo remove document if all elements in array match condition

1 Answers1