What is the difference between the $lt and $lte operators?

The distinction between the $lt and $lte operators is fundamental to understanding how comparisons function in MongoDB queries. The operator $lt stands for "less than" and is used to filter documents where the specified field's value is less than the provided value, strictly excluding equal values. In contrast, $lte represents "less than or equal to," including documents where the specified field's value is either less than or exactly equal to the provided value.

This means that when using $lte in a query, any document with a field value that matches the specified target value will be included in the results, whereas with $lt, such documents would not be included. The ability to include equal values with $lte makes it particularly useful in scenarios where boundary conditions need to be considered in filtering datasets.

Other options might suggest incorrect functionalities or characteristics of these operators. For instance, stating that both operators are identical misrepresents their distinct behaviors, while the idea that $lte is only used in arrays is incorrect, as both operators can be applied to fields of any type. Thus, recognizing that $lte includes equal values and $lt does not helps clarify their fundamental differences in MongoDB querying.