public static List<Expression> searchSourceExpressions(Expression expression) {
    return new CollectSourceExpressionsVisitor().process(expression, null);
  }
Search for subexpressions that can be queried natively, including all time series.

@param expression expression to be searched
@return searched subexpression list
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/analyze/ExpressionAnalyzer.java