You are importing data from a folder containing multiple CSV files with the same structure. You want to combine all files into a single table, but only include files that have been modified in the last 7 days. What Power Query transformation should you use?
Filtering the folder contents by 'Date Modified' before combining is correct because the folder query in Power Query contains metadata (including 'Date Modified') for each file before any binary content is read. By filtering this file-list table, you prune the set of files that the 'Combine Files' transformation will process, so only recent files are expanded and loaded. This is an efficient streaming-like approach that minimizes data extraction and refresh time.
Why this answer
Option B is correct because Power Query's Folder data source exposes file metadata columns such as Date modified, and applying a filter on that column before invoking the Combine Files transformation restricts the combined table to only files modified within the last 7 days. This keeps the import efficient and ensures the resulting single table contains only the desired recent files. Option A is wrong because 'Sample File' merely defines the file structure and does not filter by modification date.
Option C is wrong because 'Merge Queries' joins two existing queries on matching keys, not folder file metadata. Option D is wrong because filtering after combining would still load all files first, and the Date modified column is not retained in the combined result.