private boolean needBreak(Column controlColumn, int index) {
    if (isIgnoringNull() && controlColumn.isNull(index)) {
      return false;
    }

    return skipFirstPhrase(controlColumn, index) || skipSecondPhrase(controlColumn, index);
  }
skip the row which don't belong to any window(controlColumn is false or null).
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/window/ConditionWindowManager.java