Before querying data, use RETURNTYPE ('NOSREAD_SCHEMA') to inspect the column names and types inferred from the Parquet files:
SELECT *
FROM READ_NOS (
USING
LOCATION ('/az/azureopendatastorage.blob.core.windows.net/nyctlc/yellow/puYear=2016/puMonth=6/')
RETURNTYPE ('NOSREAD_SCHEMA')
STOREDAS ('PARQUET')
) AS d;
To list the files at a given location, use RETURNTYPE ('NOSREAD_KEYS'):
SELECT location(CHAR(200)), ObjectLength
FROM READ_NOS (
USING
LOCATION ('/az/azureopendatastorage.blob.core.windows.net/nyctlc/yellow/puYear=2016/puMonth=6/')
RETURNTYPE ('NOSREAD_KEYS')
STOREDAS ('PARQUET')
) AS d
ORDER BY 1;