MongoDB $or Operator

What You’ll Learn

The $or operator combines multiple conditions with logical OR. A document matches when at least one condition is true. Use it in find(), $match, and aggregation expressions for flexible filtering.

Definition and Usage

In MongoDB, the $or operator performs a logical OR on an array of expressions. In a query, a document matches when at least one condition inside $or is true. In an aggregation expression, $or returns true when any sub-expression evaluates to true.

This is especially useful when acceptable values span different fields or use different operators. For example, include products that are on sale (low price) or marked as featured.

📝 Syntax

The $or operator takes an array of two or more expressions:

{ $or: [ <expression1>, <expression2>, ... ] }

Query Example (in find or $match)

{ $or: [
  { status: "active" },
  { status: "pending" }
] }

Aggregation Expression Example (in $project)

{ $or: [
  { $gte: [ "$age", 65 ] },
  { $eq: [ "$vip", true ] }
] }

Syntax Rules

• Array required — wrap each condition as a separate object in the array.
• At least one match — if any condition is true, the document passes.
• Works in find(), $match, and aggregation expressions.
• In $match, use field-based conditions directly inside $or.
• For field-to-field comparisons, wrap with $expr and expression operators.
• Combine with $and for mixed AND/OR logic.

Examples Gallery

Find users by status, filter sale or featured products, use $or in aggregation pipelines, and compare with $in.

[
  { "_id": 1, "name": "Alice", "status": "active" },
  { "_id": 2, "name": "Bob",   "status": "pending" },
  { "_id": 3, "name": "Carol", "status": "inactive" },
  { "_id": 4, "name": "Dave",  "status": "active" }
]

db.users.find({
  $or: [
    { status: "active" },
    { status: "pending" }
  ]
})

{ "name": "Alice", "status": "active" }
{ "name": "Bob",   "status": "pending" }
{ "name": "Dave",  "status": "active" }

db.products.find({
  $or: [
    { price: { $lt: 10 } },
    { featured: true }
  ]
})

// Widget:  price 25, featured false  → excluded
// Cheap:   price 5,  featured false  → included (on sale)
// Premium: price 50, featured true   → included (featured)
// Bundle:  price 8,  featured true   → included (both match)

db.orders.aggregate([
  {
    $match: {
      $or: [
        { status: "completed" },
        { status: "shipped" }
      ]
    }
  },
  {
    $group: {
      _id: "$customerId",
      orderCount: { $sum: 1 },
      revenue: { $sum: "$total" }
    }
  }
])

db.users.find({
  $expr: {
    $or: [
      { $gte: [ "$age", 65 ] },
      { $eq: [ "$vip", true ] }
    ]
  }
})

// Seniors OR VIP members

// These are equivalent for one field:
db.users.find({
  status: { $in: [ "active", "pending" ] }
})

db.users.find({
  $or: [
    { status: "active" },
    { status: "pending" }
  ]
})

db.products.find({
  $and: [
    { inStock: true },
    {
      $or: [
        { price: { $lt: 20 } },
        { featured: true }
      ]
    }
  ]
})

// In stock AND (on sale OR featured)

🚀 Use Cases

• Status filtering — include documents with any of several allowed statuses.
• Search alternatives — match by name, email, or username in one query.
• Sales and promotions — find items on sale or featured across different fields.
• Eligibility rules — qualify users who meet any of several criteria (age, VIP, region).

💡 Best Practices