学ぶ SQL In Statement | Database and Nested Queries

セクション 1. 章 2

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Nested queries

In SQL, we can put the result of the query inside another query, and use it with operator IN:


              1234
            
SELECT title FROM songs
WHERE album_id IN
  (SELECT id FROM albums
  WHERE year > 2000)

This is a query to find songs that are created in the 21st century. First, the inner query executes with ids of albums after 2000 from table albums. Using these id's, we select such titles from songs, that album_id is among these albums. This query is quite easy and is using for multiple tables: you find some info in table1, that is inaccessible from table2, and use it for query from table2.

But we can also put constant values, here we selected all songs by 'Britney Spears', 'The Mammas & The Pappas' and 'Pink Floyd':


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SELECT id
FROM singers 
WHERE naming IN ('Britney Spears', 'The Mammas & The Pappas', 'Pink Floyd')

Now the set ('Britney Spears', 'The Mammas & The Pappas', 'Pink Floyd') is a constant list of singers, and we are searching ids of these three artists. We can also use NOT IN operator:


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SELECT id 
FROM singers
WHERE naming NOT IN ('ABBA', 'Pink Floyd', 'Mushmellow')

タスク

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Find all the songs' titles (title), where the singer's info contains 'Solo', using nested queries.

解答

実践的な練習のためにデスクトップに切り替える下記のオプションのいずれかを利用して、現在の場所から続行する

すべて明確でしたか？

フィードバックありがとうございます！

セクション 1. 章 2

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