Clarify the schema and definitions (e.g., what constitutes a call, how to handle time zones, and whether 'initiated' means caller). Then write a query that filters calls from the last 7 days, groups by user, counts calls, orders descending, and limits to 10. Be prepared to discuss edge cases like duplicate calls or missing data.
Pro tip: Mention that you would validate the query by checking the distribution of call counts and ensuring the time window is correctly aligned with the business definition of 'last 7 days' (e.g., rolling 7 days vs. previous calendar week).
Ask about the table structure (e.g., calls table with caller_id, receiver_id, call_time, etc.) and define 'initiated' (likely caller_id). Confirm the time window: last 7 days from current date or from a specific date?
Write a subquery or CTE to filter calls where call_time is within the last 7 days and caller_id is not null. Then group by caller_id and count the number of calls.
Order the aggregated results by call count descending and limit to 10. Consider using a window function if ties need special handling (e.g., RANK() to include all tied users).
Discuss how to handle ties (e.g., using RANK() instead of LIMIT), time zones, and potential data quality issues like duplicate call records.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Clarify the definitions of 'active user', 'video call', and 'yesterday' to ensure alignment with business logic. Then, structure the query to first identify the denominator (active users in France yesterday) and numerator (those who had a video call yesterday), and finally compute the percentage. Use appropriate date functions and joins to combine user activity and call data.
Pro tip: Mention that you would validate the query by checking edge cases, such as users who were active but had no calls, and ensure that the time zone is correctly handled for 'yesterday' in France. Also, discuss how you might optimize the query for performance if the tables are large.
Define what constitutes an 'active user' (e.g., logged in, performed any action) and a 'video call' (e.g., initiated or participated in a call). Confirm the time frame for 'yesterday' and the country filter for France.
Determine which tables contain user activity data, video call events, and user location information. Consider if a single table can provide all necessary data or if joins are required.
Write a subquery to count distinct active users in France for yesterday. Use appropriate date functions and filters.
Write a subquery to count distinct users in France who had a video call yesterday. Ensure that these users are also part of the active user set if the definition requires it.
Combine the numerator and denominator to compute the percentage, using division and multiplication by 100. Handle potential division by zero.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.