Contains String

https://h.api.crmls.org/RESO/OData/Office?$filter=contains(OfficeMlsId ,'626')

{
  "@odata.context": "https://h.api.crmls.org/RESO/OData/$metadata#Property",
  "value": [
    {
      "@odata.etag": "W/\"MjAwMy0wNi0yN1QwOToxNDoyNi0wNzowMA==\"",
      "AccessibilityFeatures": null,
	  .
	  .
	  .
    "ZoningDescription": null
    }
  ],
  "@odata.nextLink": "https://h.api.crmls.org/RESO/OData/Office?$filter=contains(OfficeMlsId,'626')&$skip=100"
}

Starts With String

https://h.api.crmls.org/RESO/OData/Office?$filter=startswith(OfficeMlsId,'626')

Ends With String

https://h.api.crmls.org/RESO/OData/Office?$filter=endswith(OfficeMlsId,'1036')

To Lower Case

https://h.api.crmls.org/RESO/OData/Office?$filter=tolower(OfficeMlsId)+eq+'meyer'

To Upper Case

https://h.api.crmls.org/RESO/OData/Office?$filter=toupper(OfficeMlsId)+eq+'MEYER'

Length of string

https://h.api.crmls.org/RESO/OData/Office?$filter=length(OfficeMlsId)+eq+8