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

Word filtering

Imagine that we want to extract all the hybrid cars from our database. As you understand, doing it manually is a worthless job and has to be automated.

Surely it has already been implemented! To filter observations based on columns with text use WHERE statement. For example,


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid'

This query will return all the Hybrid cars.

Please note, that in that case, you have to use single quotes, not double!

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

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

Все було зрозуміло?

Секція 2. Розділ 1

Word filtering

Imagine that we want to extract all the hybrid cars from our database. As you understand, doing it manually is a worthless job and has to be automated.

Surely it has already been implemented! To filter observations based on columns with text use WHERE statement. For example,


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid'

This query will return all the Hybrid cars.

Please note, that in that case, you have to use single quotes, not double!

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

Все було зрозуміло?

Секція 2. Розділ 1

Word filtering

Imagine that we want to extract all the hybrid cars from our database. As you understand, doing it manually is a worthless job and has to be automated.

Surely it has already been implemented! To filter observations based on columns with text use WHERE statement. For example,


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid'

This query will return all the Hybrid cars.

Please note, that in that case, you have to use single quotes, not double!

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

Все було зрозуміло?

Imagine that we want to extract all the hybrid cars from our database. As you understand, doing it manually is a worthless job and has to be automated.

Surely it has already been implemented! To filter observations based on columns with text use WHERE statement. For example,


              123
            
SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid'

This query will return all the Hybrid cars.

Please note, that in that case, you have to use single quotes, not double!

Завдання

From audi_cars table extract only cars with Automatic transmission. Extract all the columns.

Секція 2. Розділ 1