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All things SQL - tutorials, interview questions, and solutions

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How to break down user activity by day of the week in SQL. Simple to pull, takes a few minutes to write the query, and data is easy to interpret and…
Olga Berezovsky
4
A quick lookup one-pager for common DATE functions in SQL
Olga Berezovsky
How to apply CASE conditional expressions to specify a result when there are multiple conditions.
Olga Berezovsky
A practical guide on how to locate and measure a tricky product persona of adjacent users in SQL, and challenges of getting such analysis in product…
Olga Berezovsky
Some simple and quick ways to apply sampling techniques for your analysis to get random users.
Olga Berezovsky
How to connect two tables that are not related by a foreign key relationship in PostgreSQL
Olga Berezovsky
How to get the most popular features, products, or user activity in SQL
Olga Berezovsky
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