$ne for not equal in MongoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the $ne operator do in MongoDB?

The $ne operator selects documents where the value of the field is not equal to the specified value.

beginner

How would you write a MongoDB query to find documents where the field status is not equal to "active"?

Use { status: { $ne: "active" } } to find documents where status is not "active".

intermediate

Can $ne be used to check for fields that do not exist?

No, $ne checks for values not equal to a given value but does not check for field existence. Use $exists for that.

intermediate

What will this query return? { age: { $ne: 30 } }

It returns all documents where the age field is not equal to 30. Documents without an age field are also included.

beginner

Is $ne inclusive or exclusive when filtering values?

$ne is exclusive; it excludes documents where the field value matches the specified value.

What does { price: { $ne: 100 } } select?

A Documents where price is 100

B Documents where price is less than 100

C Documents where price is greater than 100

D Documents where price is not 100

$ne means 'not equal', so it selects documents where price is not 100.

If a document does not have the field status, will { status: { $ne: "active" } } match it?

A Yes, it matches documents without the field

B No, it only matches documents with the field

C Only if the field is null

D Only if the field is empty string

Documents missing the field are included because their value is not equal to 'active'.

Which operator should you use to check if a field does not exist?

A $ne

B $exists

C $gt

D $in

$exists checks if a field exists or not.

What is the result of { score: { $ne: null } }?

A Documents where score is missing

B Documents where score is null

C Documents where score is not null

D Documents where score is zero

It selects documents where score is any value except null.

Can $ne be combined with other operators in a query?

A Yes, using logical operators like $and

B No, it must be used alone

C Only with $or

D Only with $in

$ne can be combined with other operators using logical operators like $and or $or.

Explain how the $ne operator works in MongoDB queries.

Think about how you exclude a value when searching.

Describe a scenario where using $ne is helpful in a database query.

Imagine you want to find all users except those with a certain status.