Confusing error message for invalid query

[mneedham]

When following the example showing how to query Pandas DataFrames from the README, if I execute an invalid query:

print(ret_tbl.query('select b, sum(a) from __table__ group by'))

Forgetting the column to group by. The error is like this:

Code: 62. DB::Exception: Syntax error: failed at position 109 (end of query): . Expected one of: ROLLUP, CUBE, GROUPING SETS, ALL, not empty list of expressions, list of expressions, list of elements, expression with optional alias, element of expression with optional alias, lambda expression. (SYNTAX_ERROR)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/chdb/dataframe/query.py", line 112, in __str__
    return str(self.to_pandas())
               ^^^^^^^^^^^^^^^^
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/chdb/dataframe/query.py", line 64, in to_pandas
    return pandas_read_parquet(pq_reader)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/chdb/dataframe/query.py", line 318, in pandas_read_parquet
    return pd.read_parquet(path)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/pandas/io/parquet.py", line 670, in read_parquet
    return impl.read(
           ^^^^^^^^^^
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/pandas/io/parquet.py", line 272, in read
    pa_table = self.api.parquet.read_table(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/pyarrow/parquet/core.py", line 2955, in read_table
    dataset = _ParquetDatasetV2(
              ^^^^^^^^^^^^^^^^^^
  File "/Users/markhneedham/Library/Caches/pypoetry/virtualenvs/pandas-clickhouse-2MxvpB9Q-py3.11/lib/python3.11/site-packages/pyarrow/parquet/core.py", line 2495, in __init__
    [fragment], schema=schema or fragment.physical_schema,
                                 ^^^^^^^^^^^^^^^^^^^^^^^^
  File "pyarrow/_dataset.pyx", line 1357, in pyarrow._dataset.Fragment.physical_schema.__get__
  File "pyarrow/error.pxi", line 144, in pyarrow.lib.pyarrow_internal_check_status
  File "pyarrow/error.pxi", line 100, in pyarrow.lib.check_status
pyarrow.lib.ArrowInvalid: Could not open Parquet input source '<Buffer>': Parquet file size is 0 bytes

But the error is nothing to do with Parquet, so I think it shouldn't show that as part of the error message.

[auxten]

It's the same problem of #138. SQL got error and return empty result.
I will try to fix it.

[auxten]

Fixed with #105
If any error in engine, an exception will be raised with clickhouse internal error message