private Expression parseRoundFunction(
      IoTDBSqlParser.ScalarFunctionExpressionContext roundClause, boolean canUseFullPath) {
    FunctionExpression functionExpression = new FunctionExpression(ROUND_FUNCTION);
    functionExpression.addExpression(parseExpression(roundClause.input, canUseFullPath));
    if (roundClause.places != null) {
      functionExpression.addAttribute(ROUND_PLACES, parseConstant(roundClause.constant()));
    }
    return functionExpression;
  }
function for parsing file path used by LOAD statement.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/parser/ASTVisitor.java