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

HAVING some conditions

What if we want to filter grouped observations based on some condition? For example, we want to extract only those models available with Hybrid fuel types.

You can do it by grouping firstly by model, and then by fuel type filtered by condition on fueltype.


              1234
            
SELECT model
FROM audi_cars
GROUP BY model, fueltype
HAVING fueltype = 'Hybrid'

Please note, that you can use all the operators learned in the second section within HAVING statement.

Task

From the audi_cars table extract all the models available with Automatic transmission.

Task

From the audi_cars table extract all the models available with Automatic transmission.

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

Everything was clear?

Section 5. Chapter 5

HAVING some conditions

What if we want to filter grouped observations based on some condition? For example, we want to extract only those models available with Hybrid fuel types.

You can do it by grouping firstly by model, and then by fuel type filtered by condition on fueltype.


              1234
            
SELECT model
FROM audi_cars
GROUP BY model, fueltype
HAVING fueltype = 'Hybrid'

Please note, that you can use all the operators learned in the second section within HAVING statement.

Task

From the audi_cars table extract all the models available with Automatic transmission.

Task

From the audi_cars table extract all the models available with Automatic transmission.

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

Everything was clear?

Section 5. Chapter 5

HAVING some conditions

What if we want to filter grouped observations based on some condition? For example, we want to extract only those models available with Hybrid fuel types.

You can do it by grouping firstly by model, and then by fuel type filtered by condition on fueltype.


              1234
            
SELECT model
FROM audi_cars
GROUP BY model, fueltype
HAVING fueltype = 'Hybrid'

Please note, that you can use all the operators learned in the second section within HAVING statement.

Task

From the audi_cars table extract all the models available with Automatic transmission.

Task

From the audi_cars table extract all the models available with Automatic transmission.

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

Everything was clear?

What if we want to filter grouped observations based on some condition? For example, we want to extract only those models available with Hybrid fuel types.

You can do it by grouping firstly by model, and then by fuel type filtered by condition on fueltype.


              1234
            
SELECT model
FROM audi_cars
GROUP BY model, fueltype
HAVING fueltype = 'Hybrid'

Please note, that you can use all the operators learned in the second section within HAVING statement.

Task

From the audi_cars table extract all the models available with Automatic transmission.

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

Section 5. Chapter 5

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