AzureDiagnostics
| where ResourceType == "APPLICATIONGATEWAYS"
    and OperationName == "ApplicationGatewayAccess"
      and httpStatus_d ==  404
      and backendPoolName_s contains "SNWL"
| summarize AggregatedValue = count()
    by
    clientIP_s,
    host_s,
    requestUri_s,
    httpStatus_d,
    originalRequestUriWithArgs_s,
    timeStamp_t,
    userAgent_s