> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# $nor (query predicate operator)

## Definition

[`$nor`](https://www.mongodb.com/docs/manual/reference/operator/query/nor.md#mongodb-query-op.-nor) performs a logical `NOR` operation on an array of one or more query predicates and selects the documents that **fail** all the query predicates in the array. The [`$nor`](https://www.mongodb.com/docs/manual/reference/operator/query/nor.md#mongodb-query-op.-nor) has the following syntax:

```javascript
{ $nor: [ { <expression1> }, { <expression2> }, ...  { <expressionN> } ] }
```

## Examples

### `$nor` Query with Two Expressions

Consider the following query which uses only the [`$nor`](https://www.mongodb.com/docs/manual/reference/operator/query/nor.md#mongodb-query-op.-nor) operator:

```javascript
db.inventory.find( { $nor: [ { price: 1.99 }, { sale: true } ]  } )
```

This query will return all documents that:

- contain the `price` field whose value is *not* equal to `1.99` and contain the `sale` field whose value *is not* equal to `true` **or**

- contain the `price` field whose value is *not* equal to `1.99` *but* do *not* contain the `sale` field **or**

- do *not* contain the `price` field *but* contain the `sale` field whose value *is not* equal to `true` **or**

- do *not* contain the `price` field *and* do *not* contain the `sale` field

### `$nor` and Additional Comparisons

Consider the following query:

```javascript
db.inventory.find( { $nor: [ { price: 1.99 }, { qty: { $lt: 20 } }, { sale: true } ] } )
```

This query will select all documents in the `inventory` collection where:

- the `price` field value does *not* equal `1.99` **and**

- the `qty` field value is *not* less than `20` **and**

- the `sale` field value is *not* equal to `true`

including those documents that do not contain these field(s).

The exception in returning documents that do not contain the field in the [`$nor`](https://www.mongodb.com/docs/manual/reference/operator/query/nor.md#mongodb-query-op.-nor) expression is when the [`$nor`](https://www.mongodb.com/docs/manual/reference/operator/query/nor.md#mongodb-query-op.-nor) operator is used with the [`$exists`](https://www.mongodb.com/docs/manual/reference/operator/query/exists.md#mongodb-query-op.-exists) operator.

### `$nor` and `$exists`

Compare that with the following query which uses the [`$nor`](https://www.mongodb.com/docs/manual/reference/operator/query/nor.md#mongodb-query-op.-nor) operator with the [`$exists`](https://www.mongodb.com/docs/manual/reference/operator/query/exists.md#mongodb-query-op.-exists) operator:

```javascript
db.inventory.find( { $nor: [ { price: 1.99 }, { price: { $exists: false } },
                             { sale: true }, { sale: { $exists: false } } ] } )
```

This query will return all documents that:

- contain the `price` field whose value is *not* equal to `1.99` and contain the `sale` field whose value *is not* equal to `true`

**See also:**

- [`find()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.find.md#mongodb-method-db.collection.find)

- [`$or`](https://www.mongodb.com/docs/manual/reference/operator/query/or.md#mongodb-query-op.-or)

- [`$set`](https://www.mongodb.com/docs/manual/reference/operator/update/set.md#mongodb-update-up.-set)

- [`$exists`](https://www.mongodb.com/docs/manual/reference/operator/query/exists.md#mongodb-query-op.-exists)