Merge pull request #11401 from parthea/bq-improve-schema-error-msg

ENH: Improve the error message in to_gbq when schema does not match #11359

Author: jreback

doc/source/whatsnew/v0.17.1.txt

@@ -30,6 +30,7 @@ Other Enhancements
 
 - ``pd.read_*`` functions can now also accept :class:`python:pathlib.Path`, or :class:`py:py._path.local.LocalPath`
   objects for the ``filepath_or_buffer`` argument. (:issue:`11033`)
+- Improve the error message displayed in :func:`pandas.io.gbq.to_gbq` when the DataFrame does not match the schema of the destination table (:issue:`11359`)
 
 .. _whatsnew_0171.api:
 

pandas/io/gbq.py

@@ -511,7 +511,8 @@ def to_gbq(dataframe, destination_table, project_id, chunksize=10000,
             connector.delete_and_recreate_table(dataset_id, table_id, table_schema, verbose)
         elif if_exists == 'append':
             if not connector.verify_schema(dataset_id, table_id, table_schema):
-                raise InvalidSchema("The schema of the destination table does not match")
+                raise InvalidSchema("Please verify that the column order, structure and data types in the DataFrame "
+                                    "match the schema of the destination table.")
     else:
         table.create(table_id, table_schema)