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Data Manipulation using SQL

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SQL Union

UNION is an operator that concatenates results of different SQL queries:


              
1234567

            
--do not run this query
SELECT columns FROM table1
UNION
SELECT columns FROM table2
UNION
...
SELECT columns FROM tableN
copy

There is also an operator UNION ALL, and the difference is that UNION returns distinct values, unlike UNION ALL.

Requirements for using UNION operators:

  • number of columns in SELECT should be the same

  • data types and order of columns should be the same

Oppgave

Swipe to start coding

You want to get some info about songs from three decades: 1970s, 1980s, and 1990s. Find the prices of the cheapest and the most expensive songs for each decade in separate queries. You're free to use JOIN, BETWEEN, or any other operators, but you should do three separate queries and concatenate them with UNION.

Løsning

Switch to desktopBytt til skrivebordet for virkelighetspraksisFortsett der du er med et av alternativene nedenfor
Alt var klart?

Hvordan kan vi forbedre det?

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Seksjon 2. Kapittel 5
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book
SQL Union

UNION is an operator that concatenates results of different SQL queries:


              
1234567

            
--do not run this query
SELECT columns FROM table1
UNION
SELECT columns FROM table2
UNION
...
SELECT columns FROM tableN
copy

There is also an operator UNION ALL, and the difference is that UNION returns distinct values, unlike UNION ALL.

Requirements for using UNION operators:

  • number of columns in SELECT should be the same

  • data types and order of columns should be the same

Oppgave

Swipe to start coding

You want to get some info about songs from three decades: 1970s, 1980s, and 1990s. Find the prices of the cheapest and the most expensive songs for each decade in separate queries. You're free to use JOIN, BETWEEN, or any other operators, but you should do three separate queries and concatenate them with UNION.

Løsning

Switch to desktopBytt til skrivebordet for virkelighetspraksisFortsett der du er med et av alternativene nedenfor
Alt var klart?

Hvordan kan vi forbedre det?

Takk for tilbakemeldingene dine!

Seksjon 2. Kapittel 5
Switch to desktopBytt til skrivebordet for virkelighetspraksisFortsett der du er med et av alternativene nedenfor
Vi beklager at noe gikk galt. Hva skjedde?
some-alt