And

https://h.api.crmls.org/RESO/OData/OpenHouse?$filter=(OpenHouseStartTime%20ge%201000)%20and%20(OpenHouseEndTime%20le%201800)&$count=true

Or

https://h.api.crmls.org/RESO/OData/OpenHouse?$filter=(OpenHouseStartTime%20eq%201000)%20or%20(OpenHouseStartTime%20le%201300)&$count=true

Not

https://h.api.crmls.org/RESO/OData/Property/$count?$filter=not+PropertyUnits/any()