Numerical

Use filters to narrow down search results, or use them for database-like queries.

The Filter method can filter numerical fields in several ways. Supported numerical types are int, double, float, long, and their nullable equivalents. Below is a list of use cases and examples illustrating the available methods.

To search for documents where a numerical field has a value, use the Exists method. The following search finds blog posts that have an AuthorId property; it is similar to the LINQ query Where(x => x.AuthorId.HasValue).

Like all filters, you can negate it with an exclamation point (!). To find blog posts without an AuthorId, use the following code.

For exact matching, use the Match method. The following search matches blog posts with ID 42 but not those with ID 41 or 43. The LINQ equivalent is Where(x => x.Id == 42).

To find documents with a numeric field that has a value within a given range, use the InRange method. The following search matches blog posts with zero to five comments; it matches blog posts with one, two, three, four, or five comments but not those with six or seven comments.

An equivalent in LINQ is Where(x => x.NumComments >= 0 && x.NumComments <= 5).

For some numerical types, such as int, there are also the GreaterThan and LessThan methods, which make range filtering easier. For instance, given that NumComments cannot be negative; you can rewrite the previous search.

The In method lets you filter on int fields that match an explicit set of values. For instance, the following matches blog posts with one, three, or five comments.

Use the Exists, In, and Match methods for properties that implement IEnumerable<int>.

The following search, which uses Exists, matches blog posts that have at least one category ID.

The following search matches any blog post that has a category with ID 42. It does not, however, limit the result to blog posts that only have that category ID.