Running SQL queries against a parquet folder in S3

[Shaimaa]

I need to run sql queries against a parquet folder in S3. I am trying to use "read_files" but sometimes my queries fail due to errors while inferring the schema and sometimes without a specified reason. 

Sample query:

SELECT 
SUM(CASE WHEN match_result.names IS NOT NULL AND ARRAY_SIZE(match_result.names) !=0 THEN 1 ELSE 0 END)
FROM read_files('s3://folder_path')

How can I enforce the schema successfully and run my query without errors?

[shan_chandra]

 @Shaimaa  - you can divide the query into a nested query to first select all the fields from the s3 by enforcing the schema and build a nested query on top of the below example query (not syntax verified)

SELECT *
  FROM STREAM read_files(
      's3://bucket/path',
      format => 'parquet',
      schema => 'id int, ts timestamp, event string')