List of lectures for the course SQL, 13 quest level on JavaRush

What are nested queries and why do we need them?
SQL SELF
13 level,0 lecture
In this lesson, you'll find out what nested queries (or subqueries) in SQL are, why we need them, what types of nested queries exist, and how they help you solve tricky problems when working with databases.
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Using SELECT inside SELECT
SQL SELF
13 level,1 lecture
Learn how to use subqueries in SELECT to calculate aggregates, create extra columns, and do analytics right in your SQL queries. Examples are for a university training database.
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Filtering data with IN and NOT IN
SQL SELF
13 level,2 lecture
Learn how to use the IN and NOT IN operators in SQL to filter data efficiently, shorten long conditions, and make your queries more readable. We'll check out some examples, special cases with NULL, and some best practices.
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Checking if Data Exists with EXISTS and NOT EXISTS
SQL SELF
13 level,3 lecture
Learn how to use the EXISTS and NOT EXISTS operators in SQL to efficiently check for data existence, compare with IN, and avoid common mistakes when working with subqueries. Examples, explanations, and real-world tasks — all in one lecture!
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Views (`VIEW`) in PostgreSQL
SQL SELF
13 level,4 lecture
Learn how to use views (VIEW) in PostgreSQL to make complex SQL queries simpler, boost code readability, reuse selections, and control access to data. Real-life examples, tips, and what you need to know about updatable VIEWs.
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