DuckDB Already Queries Every File in a Folder, So Build the Part That Infers the Joins

Mon, 05 Oct 2026 00:00:00 +0000

Someone hands you a zip: customers.csv from the CRM, a JSON dump from the billing API, and a SQLite file from an internal app nobody has touched in two years. DuckDB will make all three queryable in a few lines of SQL, with no import step (SELECT * FROM 'customers.csv' works as written). Then you spend the afternoon working out which column joins to which. The CRM says customer_id and stores 00123. The billing API says customerId and stores 123. The SQLite table has a column called customer holding the text 123. Same customer, three spellings.

Data Engineering on App Coding

DuckDB Already Queries Every File in a Folder, So Build the Part That Infers the Joins