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Apprendre Aliases | Selecting
SQL Basics
course content

Contenu du cours

SQL Basics

SQL Basics

1. Selecting
2. Filtering
3. Aggregating
4. Sorting
5. Grouping
6. Practicing

book
Aliases

The outputs of the last two tasks were single columns with single values. If you noticed, this column had a name count, which is not, to be honest representative. Seems like it's only a matter of taste. But in the future, when you will work with multiple tables, will join one table to another, the same names will be a huge problem. Even from the point of interpreting the data.

In SQL you can easily declare a new name to a column by using AS statement. For example,

12
SELECT COUNT(DISTINCT(country)) AS "number of countries" FROM visitors
copy

This query will return a single value in the single column named number of countries, which is much readable than count.

Please note, that the aliases you use must be placed within double-quotes. Using single quotes will result in SQL error!

Tâche

Swipe to start coding

Extract unique types of fuel consumed by cars (column fueltype) and name this column as "Fuel type".

Solution

Switch to desktopPassez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous
Tout était clair ?

Comment pouvons-nous l'améliorer ?

Merci pour vos commentaires !

Section 1. Chapitre 8
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book
Aliases

The outputs of the last two tasks were single columns with single values. If you noticed, this column had a name count, which is not, to be honest representative. Seems like it's only a matter of taste. But in the future, when you will work with multiple tables, will join one table to another, the same names will be a huge problem. Even from the point of interpreting the data.

In SQL you can easily declare a new name to a column by using AS statement. For example,

12
SELECT COUNT(DISTINCT(country)) AS "number of countries" FROM visitors
copy

This query will return a single value in the single column named number of countries, which is much readable than count.

Please note, that the aliases you use must be placed within double-quotes. Using single quotes will result in SQL error!

Tâche

Swipe to start coding

Extract unique types of fuel consumed by cars (column fueltype) and name this column as "Fuel type".

Solution

Switch to desktopPassez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous
Tout était clair ?

Comment pouvons-nous l'améliorer ?

Merci pour vos commentaires !

Section 1. Chapitre 8
Switch to desktopPassez à un bureau pour une pratique réelleContinuez d'où vous êtes en utilisant l'une des options ci-dessous
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