static <T> T maybeGet(Record record, TableField<Record, T> field, T defaultValue) {
    if (record.fieldsRow().indexOf(field) < 0) {
      return defaultValue;
    } else {
      T result = record.get(field);
      return result != null ? result : defaultValue;
    }
  }
returns the default value if the column doesn't exist or the result was null
zipkin-storage/mysql-v1/src/main/java/zipkin2/storage/mysql/v1/Schema.java