Apprendre 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.

Tâche

Swipe to start coding

Extract all unique combinations of model and transmission

Solution

Passez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous

Tout était clair ?

Merci pour vos commentaires !

Section 1. Chapitre 5

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Posez n'importe quelle question ou essayez l'une des questions suggérées pour commencer notre discussion

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.

Tâche

Swipe to start coding

Extract all unique combinations of model and transmission

Solution

Passez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous

Tout était clair ?

Merci pour vos commentaires !

Section 1. Chapitre 5

single

Glissez pour afficher le menu

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.

Tâche

Swipe to start coding

Extract all unique combinations of model and transmission

Solution

Passez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous

Tout était clair ?

Merci pour vos commentaires !

Unique values from multiple columns

Solution

Awesome!

Unique values from multiple columns

Solution

Awesome!

Unique values from multiple columns

Solution