List of lectures for the course SQL, 7 quest level on JavaRush

Intro to Aggregate Functions
SQL SELF
7 level,0 lecture
Get to know aggregate functions in SQL: how they help you analyze huge amounts of data, count, sum up, find minimums and maximums, and also deal with missing values (NULL).
Open
Counting Rows with COUNT() and Its Variations
SQL SELF
7 level,1 lecture
In this lecture, you'll learn how to use the COUNT() function in SQL to count rows, the difference between COUNT(*), COUNT(column), and COUNT(DISTINCT column), plus some common mistakes when working with this function.
Open
Summing Data with SUM() — Syntax and Examples
SQL SELF
7 level,2 lecture
Learn how to use the aggregate function SUM() in SQL to calculate totals for numeric columns. Syntax examples, working with conditions, handling NULL, and common mistakes — everything you need to confidently use SUM() in practice.
Open
Averages with AVG() — calculating averages by columns
SQL SELF
7 level,3 lecture
Learn how to use the aggregate function AVG() in SQL to calculate averages by columns, how it works with NULL, how to round the result, and how to filter data before calculating the average.
Open
Minimum and Maximum Values: MIN() and MAX()
SQL SELF
7 level,4 lecture
Learn how to find minimum and maximum values in SQL tables using the aggregate functions MIN() and MAX(). Examples for numbers, strings, dates, and some quirks with NULL.
Open