SQL Aliases

Ususally in database tables and columns can have long names. When you work with multiple tables, you should write the name of the column with the name of the table to define the column, for example, users.user_id and messages.date_created. To avoid overtyping, in SQL we use Aliases. They allow us to give temporary names to column or tables.

For example, for our table:


              123
            
SELECT album, singer as some_label
FROM songs as t
WHERE t.album = 'The Dark Side of the Moon' OR t.singer = 'Mushmellow'

Here you use table songs as t. In the console, instead of singer, your column has a label some_label. This example is not demonstrative enough, but in the next section we'll work with multiple tables, and temporary names may be useful.

Opgave

Swipe to start coding

Find top-3 newest songs, their singers, and years, but use songs table as s. Make the column title displayed with the label name.

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 3. Kapitel 10

SQL Aliases

For example, for our table:


              123
            
SELECT album, singer as some_label
FROM songs as t
WHERE t.album = 'The Dark Side of the Moon' OR t.singer = 'Mushmellow'

Opgave

Swipe to start coding

Find top-3 newest songs, their singers, and years, but use songs table as s. Make the column title displayed with the label name.

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 3. Kapitel 10

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