Data Engineer

Given two tables t1 and t2. List all types of joins you know, and the result of the query select * from t1 <join> t2 on t1.t = t2.t for each. |t1.t| ------ 1 2 4 null ------ |t2.t| ------ 1 3 null null

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Tell us about your experience with Greenplum, DBT, and Data Vault. Why did you switch from a snowflake model to Data Vault?

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What is the difference between iterating over a string and iterating over a tuple in Python? What are the basic types and how does this affect performance?

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Compare two solutions for the memory consumption of unit search: 1) loop with variables, 2) split('0') + list comprehension + max()

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Describe the methods of SQL query optimization you have applied. How did you reduce the execution time from 12-15 seconds?

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What motivates you at work? List your strengths in terms of hard skills.

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Given a string of zeros and ones. It is necessary to write a function func() that returns the maximum number of consecutive ones. For example: func("010111011") -> 3

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Given two tables t1 and t2. The task is to list all types of joins you know, and the query result select * from t1 <join> t2 on t1.t = t2.t for each of them. |t1.t| ------ 1 2 4 null ------ |t2.t| ------ 1 3 null null cross 1 1 - null null - INNER JOIN [phone] LEFT JOIN 1 - 1 2 - NULL 4 - NULL NULL - NULL RIGHT JOIN [phone] NULL - 3 NULL - NULL NULL - NULL FULL JOIN [phone] - NULL 4 - NULL NULL - 3 null - NULL null - NULL null - NULL

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What types of JOIN algorithms exist in PostgreSQL and how does Hash Join differ from Nested Loop Join? In which cases is Hash Join not applicable?

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Tell about the most complex or interesting task you had to solve.

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