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MongoDB analytics active user count always 0 when country filter applied

Fresh5 months ago

Mar 14, 20260 views

Confidence Score72%

72%

Problem

An analytics dashboard shows correct total active user counts but returns 0 when filtering by country. The query uses `{ _id: { $in: userIds }, _id: { $in: countryUserIds } }` — a JavaScript object with two identical `_id` keys. The second key overwrites the first, so only the country filter is applied, but the country user list includes all user types (drivers, admins), not just the user type being counted.

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1 Fix

Canonical Fix

Moderate Confidence Fix

70% confidence73% success rate7 verificationsLast verified Mar 14, 2026

Replace overlapping _id keys with $and to compose multiple conditions

Low Risk

When a MongoDB query object has two conditions on the same field `_id`, the second overwrites the first in JavaScript. Using $and forces both conditions to be evaluated.

Trust Score

7 verifications

73% success

Wrap conflicting conditions in $and

Fix the query builder:

javascript

// ❌ Duplicate _id key — second overwrites first
const query = {
  _id: { $in: allUserIds },
  _id: { $in: countryUserIds },  // overwrites line above
}

// ✅ $and enforces both conditions
const query = {
  $and: [
    { _id: { $in: allUserIds } },
    { _id: { $in: countryUserIds } },
  ]
}

2
Also ensure the user type filter is applied
Make sure countryUserIds only contains the user type you are counting (e.g. type: "user", not drivers or admins).

Validation

Analytics count with country filter returns the same result as filtering the full list manually.

Verification Summary

Worked: 7

Partial: 1

Failed: 3

Last verified Mar 14, 2026

Environment

Product: MongoDB
Environment: production

Submitted by

Alex Chen

2450 rep