Lære Unique values from multiple columns

But what if we want to know, for example, unique pairs 'country-city' of our site visitors? Surely, we can extract unique countries (like in the previous chapter) and unique cities. But then we have to connect each city to the country manually.

This task can be solved by the same DISTINCT, but this time with two columns. For example,


              12
            
SELECT DISTINCT(country), city
FROM visitors

The DISTINCT statement will return all the unique combinations of columns you chose. Using parentheses is not mandatory, i.e. you for the example above you can write DISTINCT country, city. But placing multiple columns within DISTINCT parentheses will return only one column of all unique combinations in (country, city) format.

Opgave

Swipe to start coding

Extract all unique combinations of model and transmission

Løsning

Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder

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Sektion 1. Kapitel 5

single

Spørg AI

Spørg om hvad som helst eller prøv et af de foreslåede spørgsmål for at starte vores chat

This task can be solved by the same DISTINCT, but this time with two columns. For example,


              12
            
SELECT DISTINCT(country), city
FROM visitors

The DISTINCT statement will return all the unique combinations of columns you chose. Using parentheses is not mandatory, i.e. you for the example above you can write DISTINCT country, city. But placing multiple columns within DISTINCT parentheses will return only one column of all unique combinations in (country, city) format.

Opgave

Swipe to start coding

Extract all unique combinations of model and transmission

Løsning

Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder

Var alt klart?

Tak for dine kommentarer!

Sektion 1. Kapitel 5

single

Stryg for at vise menuen

This task can be solved by the same DISTINCT, but this time with two columns. For example,


              12
            
SELECT DISTINCT(country), city
FROM visitors

The DISTINCT statement will return all the unique combinations of columns you chose. Using parentheses is not mandatory, i.e. you for the example above you can write DISTINCT country, city. But placing multiple columns within DISTINCT parentheses will return only one column of all unique combinations in (country, city) format.

Opgave

Swipe to start coding

Extract all unique combinations of model and transmission

Løsning

Skift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder

Var alt klart?

Tak for dine kommentarer!

Unique values from multiple columns

Løsning

Awesome!

Unique values from multiple columns

Løsning

Awesome!

Unique values from multiple columns

Løsning