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

Combining conditions

Often it's not enough to check for only one condition. What if we want to check if multiple conditions hold at the same time? Or at least one of them?

Conditions in SQL can be combined by using AND and OR statements within WHERE block. AND checks if all the conditions hold while OR checks if at least one of the conditions holds. For example, we can combine conditions from the two previous chapters: filter for hybrid cars with mileage less than 5000 miles.


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid' AND mileage < 5000

Also, we can extract only either cars with Automatic transmission either with an engine size less than 3 by using OR statement.


              123
            
SELECT *
FROM audi_cars
WHERE transmission = 'Automatic' OR enginesize < 3

Завдання

Swipe to show code editor

From audi_cars table extract only Diesel cars (fueltype column) with mileage less than 2000.

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

Все було зрозуміло?

Дякуємо за ваш відгук!

Секція 2. Розділ 3

Combining conditions

Often it's not enough to check for only one condition. What if we want to check if multiple conditions hold at the same time? Or at least one of them?


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid' AND mileage < 5000

Also, we can extract only either cars with Automatic transmission either with an engine size less than 3 by using OR statement.


              123
            
SELECT *
FROM audi_cars
WHERE transmission = 'Automatic' OR enginesize < 3

Завдання

Swipe to show code editor

From audi_cars table extract only Diesel cars (fueltype column) with mileage less than 2000.

Все було зрозуміло?

Дякуємо за ваш відгук!

Секція 2. Розділ 3

Combining conditions

Often it's not enough to check for only one condition. What if we want to check if multiple conditions hold at the same time? Or at least one of them?


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid' AND mileage < 5000

Also, we can extract only either cars with Automatic transmission either with an engine size less than 3 by using OR statement.


              123
            
SELECT *
FROM audi_cars
WHERE transmission = 'Automatic' OR enginesize < 3

Завдання

Swipe to show code editor

From audi_cars table extract only Diesel cars (fueltype column) with mileage less than 2000.

Все було зрозуміло?

Дякуємо за ваш відгук!

Often it's not enough to check for only one condition. What if we want to check if multiple conditions hold at the same time? Or at least one of them?


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid' AND mileage < 5000

Also, we can extract only either cars with Automatic transmission either with an engine size less than 3 by using OR statement.


              123
            
SELECT *
FROM audi_cars
WHERE transmission = 'Automatic' OR enginesize < 3

Завдання

Swipe to show code editor

From audi_cars table extract only Diesel cars (fueltype column) with mileage less than 2000.

Секція 2. Розділ 3