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COUNT DISTINCT: Unique Genres in Rock

intermediate~5 min20 pts
📊 View Insights

Problem

Count how many unique composers have created Rock music. Use COUNT with DISTINCT to count unique values.

Write a query to count unique composers in the Rock genre.

Schema: Track

ColumnType
TrackIdINTEGER (Primary Key)
NameTEXT
AlbumIdINTEGER (Foreign Key → Album.AlbumId)
MediaTypeIdINTEGER (Foreign Key)
GenreIdINTEGER (Foreign Key → Genre.GenreId)
ComposerTEXT
MillisecondsINTEGER
BytesINTEGER
UnitPriceNUMERIC(10,2)

Schema: Genre

ColumnType
GenreIdINTEGER (Primary Key)
NameTEXT

Requirements:

  • Join Track with Genre
  • Filter for Genre.Name = 'Rock'
  • Count distinct (non-NULL) composers
  • Return as UniqueComposers
COUNTDISTINCTJOIN
📊
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SQL Editor

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