private boolean skipFirstPhrase(Column controlColumn, int index) {
    if (!isFirstSkip) {
      return false;
    }

    return controlColumn.isNull(index) || !controlColumn.getBoolean(index);
  }
skip the row remains in the current window(controlColumn is true).
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/window/ConditionWindowManager.java