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SQL Basics
course content

Course Content

SQL Basics

SQL Basics

1. Selecting
The very first meet with the databaseSELECTing certain columnsLIMITing resultsUnique values from columnUnique values from multiple columnsHow many?How many unique?AliasesTables aliases
2. Filtering
Word filteringNumber filteringCombining conditionsFiltering by numeric intervalMultiple filtering on one columnLIKE filteringNOT like this!
3. Aggregating
MINimal and MAXimal valuesSUMming valuesMean valuesROUNDing
4. Sorting
Sorting by one columnSorting in DESCending orderThe cheapest carSorting by multiple columns
5. Grouping
What is grouping?More aggregate statistics!Grouping by multiple columnsThe cheapest combinationHAVING some conditionsLeast consuming carsFiltering group size
6. Practicing
Challenge: Unique combinationsChallenge: Average Q-series cars priceChallenge: The cheapest new A-series carsChallenge: Relation between engine size and fuel consumptionChallenge: Mileage and manufacture year - is there relation?Challenge: Average price for each model and yearChallenge: The most expensive transmission + engine size combinations

bookGrouping by multiple columns

Can we group observations based on multiple columns? For example, we can group all cars by year and engine size and find the most expensive within these.

To group by multiple columns use the same approach as for sorting by multiple columns: just put it within GROUP BY statement separated with a comma. The query for the example above will look like this:


              
123

            
SELECT year, enginesize, AVG(price)
FROM audi_cars
GROUP BY year, enginesize
copy

Task

From the audi_cars table calculate the maximum, average, and minimum price for each model manufactured in different years.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 5. Chapter 3
toggle bottom row

bookGrouping by multiple columns

Can we group observations based on multiple columns? For example, we can group all cars by year and engine size and find the most expensive within these.

To group by multiple columns use the same approach as for sorting by multiple columns: just put it within GROUP BY statement separated with a comma. The query for the example above will look like this:


              
123

            
SELECT year, enginesize, AVG(price)
FROM audi_cars
GROUP BY year, enginesize
copy

Task

From the audi_cars table calculate the maximum, average, and minimum price for each model manufactured in different years.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 5. Chapter 3
toggle bottom row

bookGrouping by multiple columns

Can we group observations based on multiple columns? For example, we can group all cars by year and engine size and find the most expensive within these.

To group by multiple columns use the same approach as for sorting by multiple columns: just put it within GROUP BY statement separated with a comma. The query for the example above will look like this:


              
123

            
SELECT year, enginesize, AVG(price)
FROM audi_cars
GROUP BY year, enginesize
copy

Task

From the audi_cars table calculate the maximum, average, and minimum price for each model manufactured in different years.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Can we group observations based on multiple columns? For example, we can group all cars by year and engine size and find the most expensive within these.

To group by multiple columns use the same approach as for sorting by multiple columns: just put it within GROUP BY statement separated with a comma. The query for the example above will look like this:


              
123

            
SELECT year, enginesize, AVG(price)
FROM audi_cars
GROUP BY year, enginesize
copy

Task

From the audi_cars table calculate the maximum, average, and minimum price for each model manufactured in different years.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Section 5. Chapter 3
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
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