Columnar file formats store a table one column at a time, so a report reads and compresses only the columns it needs. This post compares rows and columns on a tiny table, explains how a Parquet file is laid out, and measures the size difference in SQL Server 2025.
Querying External Files With PolyBase
PolyBase and SQL Server external tables expose CSV and Parquet files through schemas, while query plans show whether filters reduce remote work.
Importing CSV File into SQL Server: SQL in Sixty Seconds #018
Importing CSV file data into SQL Server means matching the file to a table, loading it and checking the result. The tests here show a bad row skipped after a printed error, a text staging load, and the encoding and line ending settings that break a load.
Moving Data Out of SQL Server in Open Formats
Move SQL Server data into open formats such as CSV, JSON, and Parquet while preserving types, NULLs, encoding, and readable files.
Reading Fixed-Width Text Files With OPENROWSET and a Format File
Read fixed-width text files with OPENROWSET and an XML format file, trim fields, validate conversions, and load only acceptable rows.
Importing CSV Files Without Surprises
Importing CSV files Without Surprises covers quoted delimiters, UTF-8 encoding, dates, staging tables, and SQL Server BULK INSERT FORMAT = ‘CSV’.
Loading Large Files Fast With BULK INSERT
BULK INSERT loads large SQL Server files through a tested format, accessible path, staging table, measured batches, and final validation.