Dataford
Interview QuestionsInterview GuidesExperiencesMock InterviewsPricing
Get started
SQL And Data Manipulation
00:00
5 left

SQL And Data Manipulation

MediumSQL · PostgreSQL

Problem

Tell me about your SQL skills and how you use tools like BigQuery in past projects or internships.

Demonstrate your answer by summarizing project query activity from the provided tables. Include only projects with at least one BigQuery run and at least two successful runs.

Output

  1. One row per qualifying project, with project_name, total_runs, successful_runs, success_rate, and avg_duration_seconds
  2. Sort by success_rate descending, average duration ascending, then project_name ascending

Schema

projects
ColumnTypeDescription
project_idPKINTUnique project identifier
project_nameVARCHAR(100)Project name
query_runs
ColumnTypeDescription
run_idPKINTUnique query run identifier
project_idINTProject associated with the run
tool_nameVARCHAR(50)SQL or analytics tool used for the run
run_dateDATEDate when the query ran
statusVARCHAR(20)Run outcome
duration_secondsDECIMAL(10,2)Query duration in seconds
Tablesprojectsquery_runs
Interviewer

Your question is SQL And Data Manipulation. Start with the requirements and the two tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

You need to log in / sign up to run or submit.
CodePostgreSQL
You need to log in / sign up to run or submit.Ln 1
Run your query to see results here.