How can I dynamically add Query parameters in Web.Contents call?

Ah figured it out

(ResourceUri as text, metricnames as text, aggregation as text, interval as text, timespan as text, optional top as text, optional orderby as text) =>
let
    QueryParams =  Record.Combine({
    [aggregation = aggregation, interval = interval, metricnames = metricnames, timespan=timespan],
    if orderby<>"" and orderby <> null then  [orderby = orderby] else [],
    if top<>"" and top <> null then  [top = top] else []
}),
    Source = Json.Document(Web.Contents(
            "https://management.azure.com/" & 
            ResourceUri & "/providers/microsoft.insights/metrics?api-version=2018-01-01&%24filter=CollectionName%20eq%20%27*%27%20and%20DatabaseName%20eq%20%27*%27",
            [Query=QueryParams])),