Course Content

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

Unique values from column

In real life, you may work with big tables containing thousands of rows and lots of columns. For example, you may have a database with all the users who have visited your site, and you want to know all the countries that attended your site.

In SQL, to extract unique values from the column use the DISTINCT statement. For example, to extract unique countries from the table visitors use:


              12
            
SELECT DISTINCT(country)
FROM visitors

Task

From the audi_cars table extract all the unique models of cars.

Task

From the audi_cars table extract all the unique models of cars.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Section 1. Chapter 4

Unique values from column

In SQL, to extract unique values from the column use the DISTINCT statement. For example, to extract unique countries from the table visitors use:


              12
            
SELECT DISTINCT(country)
FROM visitors

Task

From the audi_cars table extract all the unique models of cars.

Task

From the audi_cars table extract all the unique models of cars.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Section 1. Chapter 4

Unique values from column

In SQL, to extract unique values from the column use the DISTINCT statement. For example, to extract unique countries from the table visitors use:


              12
            
SELECT DISTINCT(country)
FROM visitors

Task

From the audi_cars table extract all the unique models of cars.

Task

From the audi_cars table extract all the unique models of cars.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

In SQL, to extract unique values from the column use the DISTINCT statement. For example, to extract unique countries from the table visitors use:


              12
            
SELECT DISTINCT(country)
FROM visitors

Task

From the audi_cars table extract all the unique models of cars.

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Section 1. Chapter 4

Switch to desktop for real-world practiceContinue from where you are using one of the options below