The Parquet file format is a column-oriented data storage format designed for efficient data storage and retrieval. It has become widely adopted as a file interchange format, with ClickHouse being one of the popular tools used to read and write this format. ClickHouse Local, an easy-to-use version of ClickHouse, can be used to query and transform Parquet files using SQL without writing any Python code. The file function in ClickHouse allows users to read schemas, query local and S3-hosted Parquet files, and perform various operations such as filtering, grouping, and aggregating data. Writing Parquet files with ClickHouse can be achieved through the INTO FUNCTION clause, which supports writing to local files or object storage like S3. The PARTITION BY clause allows users to write Parquet files in a partitioned format, which can help limit file sizes. ClickHouse also provides an efficient way to convert files between formats using the file function. Additionally, ClickHouse can load data from local Parquet files or S3 using the INFILE and s3 functions, respectively. The performance of these operations is significantly better when using ClickHouse with a MergeTree table schema, as it allows for indexes and format-specific optimizations to be exploited.