Inner join of two CSV datasetsCodingTwo systems export CSV data that you need to combine. Implement: Each dataset is a list of lines. The first line is a header of comma-separated column names. Every other line is a…
Last asked Apr 2026
#joins
Total population of a city across zip codes in SQLCodingFour tables describe geography: country, state, city and zip code, each pointing to its parent, and the population is stored per zip code. Write a query that returns the total…Last asked Feb 2026
SQL: each user's first share and closest collaboratorCodingTables hold users, files and user actions on files. Write SQL that finds the first time each user shared a file, then a query for each user's closest collaborator, the person they…Last asked Jan 2026
Library database SQL: unreturned copies, top books and referral gapsCodingA library schema has tables for books, copies, members, checkouts, reservations and authors. Write the queries: 1. How many copies are in good condition and not yet returned?…Last asked Nov 2025
SQL screening with joins and window functionsCodingA SQL screen covering joins, aggregation and window functions over product data. Reported on 1point3acres' Notion bank; reconstructed in our own words.