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

MINimal and MAXimal values

Now it's time to talk about aggregate functions - functions that calculate some summary stats. Let's start with extremal summary stats - minimum and maximum values.

To find the minimum (or maximum) value in the column use MIN (or MAX) functions followed by column name. For example, we can find out the cheapest car with Automatic transmission.


              123
            
SELECT MIN(price)
FROM audi_cars
WHERE transmission = 'Automatic'

Please note, that unlike for DISTINCT function you need to use parentheses for MIN and MAX functions.

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

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 1

MINimal and MAXimal values

Now it's time to talk about aggregate functions - functions that calculate some summary stats. Let's start with extremal summary stats - minimum and maximum values.

To find the minimum (or maximum) value in the column use MIN (or MAX) functions followed by column name. For example, we can find out the cheapest car with Automatic transmission.


              123
            
SELECT MIN(price)
FROM audi_cars
WHERE transmission = 'Automatic'

Please note, that unlike for DISTINCT function you need to use parentheses for MIN and MAX functions.

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

Все було зрозуміло?

Секція 3. Розділ 1

MINimal and MAXimal values

Now it's time to talk about aggregate functions - functions that calculate some summary stats. Let's start with extremal summary stats - minimum and maximum values.

To find the minimum (or maximum) value in the column use MIN (or MAX) functions followed by column name. For example, we can find out the cheapest car with Automatic transmission.


              123
            
SELECT MIN(price)
FROM audi_cars
WHERE transmission = 'Automatic'

Please note, that unlike for DISTINCT function you need to use parentheses for MIN and MAX functions.

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

Все було зрозуміло?

Now it's time to talk about aggregate functions - functions that calculate some summary stats. Let's start with extremal summary stats - minimum and maximum values.

To find the minimum (or maximum) value in the column use MIN (or MAX) functions followed by column name. For example, we can find out the cheapest car with Automatic transmission.


              123
            
SELECT MIN(price)
FROM audi_cars
WHERE transmission = 'Automatic'

Please note, that unlike for DISTINCT function you need to use parentheses for MIN and MAX functions.

Завдання

From the audi_cars table find out the price of the most expensive Diesel car (fueltype column).

Секція 3. Розділ 1