Data Analyst

Have you tried your skills in large technology companies, such as VK, Yandex?

Can you tell me more about JOIN operations and how they differ from each other?

How do you feel about a mixed work format, where routine regular tasks are combined with suddenly arising urgent tasks?

Junior

СБЕР

Write Python code that computes the dot product of two RLE-compressed vectors in a single pass.

Intern

Яндекс

You need to write a query that returns the second to last loaded record by id: |id |msisdn |tarif_plan_id|account_id|raw_dt | |------------|-----------|-------------|----------|-----------| |[phone]|5842 |4979 |[phone]| |[phone]|4563 |0832 |[phone]| |[phone]|4563 |0832 |[phone]| There is a table of subscribers with change history. Each record for a subscriber is valid within the period from valid_from_dt to valid_to_dt. If one record is closed, the next record starts from the same date. There should be only one active record for each subscriber in the interval [valid_from_dt, valid_to_dt]. select * from abnt |id|valid_from_dt|valid_to_dt|msisdn |tarif_plan_id|account_id| |--|-------------|-----------|-------------|-------------|----------| |1 |[phone] |[phone] |[phone] |4375 |4979 | |1 |[phone] |[phone] |[phone] |5842 |4979 | |2 |[phone] |[phone] |[phone] |4563 |5326 | |2 |[phone] |[phone] |[phone] |4563 |0832 | You need to write a query that returns records with incorrect closing dates. |id|valid_from_dt|valid_to_dt|msisdn |tarif_plan_id|account_id| |--|-------------|-----------|-------------|-------------|----------| |1 |[phone] |[phone] |[phone] |5842 |4979 | |2 |[phone] |[phone] |[phone] |4563 |5326 |

Middle

МТС

In one request, there is a window function and grouping — which executes first?

What is the logical order of execution for FROM, JOIN, GROUP BY, and SELECT in this SQL query?

Intern

Яндекс

How will you evaluate, once you are with us, whether the position suits you or will become boring? What indicators will you look at?

Tell us a little about yourself, your experience, key moments

What is logistic regression and where does its loss function come from?

How do you understand the tasks and functions of the senior specialist position based on the detailed description provided by the manager?

Tell about the difficulties and mistakes in the project.

Intern

Т-Банк

Problem: a thousand users place one order each and leave — how is this seen in metrics and what to do?

Intern

СБЕР Звук

Business case: a new project with new transactions has started. How would you set up monitoring for suspicious transactions if you know nothing about this project?

Intern

Т-Банк

Which North Star metric should be chosen for car sharing?

Intern

СБЕР Звук

select t.* from userentry t limit 10

Intern

СБЕР Звук

How interested are you in machine learning and would you like to apply it as a tool in your work?

Intern

Яндекс

Tell me, what is a Type II statistical error?

-- 2. The campaigns table has been fixed: duplicate entries removed, a primary key (PK) added. -- More campaigns have been conducted, and due to bugs, users started experiencing failed delivery attempts, and some couldn't see the message at all. -- Regarding the promotional campaigns sent to users: -- 2.1 Write a query that outputs the number of users who successfully received the communication for each campaign. -- 2.2 Modify the query to output: the number of users who did not receive any successful communication at all, for each campaign. -- 3. An additional field – event_timestamp – has been added to the communications table, representing the date and time of the communication delivery event in the format '%Y-%m-%d %H:%M:%S'. -- For all campaigns, including those not launched, calculate the metric: the proportion of users for whom the delivery of a successful message was achieved on the first attempt. -- You can use window functions, or do without them, but it is important to write an optimal query.

Intern

Яндекс

If we talk now about priorities — what is important to you when choosing a job, what do you pay attention to?