code: func selectFields(val interface{} /*, opts Options*/) (statement string) {
  	fields := structs.ListExportedFields(val, cqlExported)
  	ret := bytes.Buffer{}
  	first := true
  	for _, field := range fields {
  		fieldName, exported := fieldName(field)
  		if exported {
  			if first {
  				first = false
  			} else {
  				ret.WriteString(", ")
  			}
  
  			ret.WriteString(fieldName)
  		}
  	}
  
  	return ret.String()
  }
docs: // selectFields generates comma separated field names string