Зміст курсу

SQL Basics

1. Selecting

The very first meet with the database SELECTing certain columns LIMITing results Unique values from column Unique values from multiple columns How many?How many unique?Aliases Tables aliases

2. Filtering

Word filtering Number filtering Combining conditions Filtering by numeric interval Multiple filtering on one column LIKE filtering NOT like this!

3. Aggregating

MINimal and MAXimal values SUMming values Mean values ROUNDing

4. Sorting

Sorting by one column Sorting in DESCending order The cheapest car Sorting by multiple columns

5. Grouping

What is grouping?More aggregate statistics!Grouping by multiple columns The cheapest combination HAVING some conditions Least consuming cars Filtering group size

6. Practicing

Challenge: Unique combinations Challenge: Average Q-series cars price Challenge: The cheapest new A-series cars Challenge: Relation between engine size and fuel consumption Challenge: Mileage and manufacture year - is there relation?Challenge: Average price for each model and year Challenge: The most expensive transmission + engine size combinations

SUMming values

There is one more function that has to be implemented - function for summing values. For example, we may want to calculate the total revenue for a certain item.

To sum values in column use SUM function followed by column which values you want to sum. For our abstract example,


              123
            
SELECT SUM(revenue)
FROM sells
WHERE item = 'Sofa'

Please note, that SUM function works only with numeric columns.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Перейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів

Все було зрозуміло?

Секція 3. Розділ 2

SUMming values

There is one more function that has to be implemented - function for summing values. For example, we may want to calculate the total revenue for a certain item.

To sum values in column use SUM function followed by column which values you want to sum. For our abstract example,


              123
            
SELECT SUM(revenue)
FROM sells
WHERE item = 'Sofa'

Please note, that SUM function works only with numeric columns.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Все було зрозуміло?

Секція 3. Розділ 2

SUMming values

There is one more function that has to be implemented - function for summing values. For example, we may want to calculate the total revenue for a certain item.

To sum values in column use SUM function followed by column which values you want to sum. For our abstract example,


              123
            
SELECT SUM(revenue)
FROM sells
WHERE item = 'Sofa'

Please note, that SUM function works only with numeric columns.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Все було зрозуміло?

There is one more function that has to be implemented - function for summing values. For example, we may want to calculate the total revenue for a certain item.

To sum values in column use SUM function followed by column which values you want to sum. For our abstract example,


              123
            
SELECT SUM(revenue)
FROM sells
WHERE item = 'Sofa'

Please note, that SUM function works only with numeric columns.

Завдання

From the audi_cars table calculate the total tax for all RS4 cars.

Секція 3. Розділ 2