             }
         }
 
-        /// Returns the `Database.QueryData` value if it exists.
+        /// Returns the values as an array of query data, if possible.
         public func data() -> [Database.QueryData]? {
             switch storage {
             case .data(let data): return [data]

}

extension QueryBuilder {
    /// Applies a comparison filter to this query.
    @discardableResult
    public func filter<M, T>(_ joined: M.Type, _ key: KeyPath<M, T>, _ type: DatabaseQuery<M.Database>.FilterType, _ value: DatabaseQuery<M.Database>.FilterValue) throws -> Self
        where M: Fluent.Model, M.Database == Model.Database

        }
    }

    /// Supported filter values.
    public struct FilterValue {
        enum QueryFilterValueStorage {
            case field(Database.QueryField)
