In MongoDB, which operator would you use to check if a value is not equal to another?

The operator used in MongoDB to check if a value is not equal to another is the $ne operator. This operator is specifically designed for comparisons where you want to filter documents based on non-equality. When using $ne in a query, you can specify a field and provide a value; the query will return all documents where the field's value is not equal to the specified value.

For example, if you wanted to find all documents in a collection where the field "status" is not equal to "active," you would use a query like this: { "status": { "$ne": "active" } }. This directly targets the requirement for checking values that do not match a certain criteria.

In contrast, other operators like $gt (greater than), $eq (equal to), and $gte (greater than or equal to) serve different purposes in filtering and comparing data. $gt checks if one value is greater than another, $eq checks for equality, and $gte checks for greater than or equal to, which do not address the need for non-equality that $ne satisfies.