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Queries with derived tables (I)

The focus of this lesson is derived tables. You can use derived tables when you want to break down a complex query into smaller steps. A derived table is a query which is used in the place of a table. Derived tables are a great solution if you want to create intermediate calculations that need to be used in a larger query.

In this exercise, you will calculate the maximum value of the blood glucose level for each record by age.

Questo esercizio fa parte del corso

Intermediate SQL Server

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Istruzioni dell'esercizio

  • Return MaxGlucose from the derived table.
  • Join the derived table to the main query on Age.

Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

SELECT a.RecordId, a.Age, a.BloodGlucoseRandom, 
-- Select maximum glucose value (use colname from derived table)    
       b.___
FROM Kidney a
-- Join to derived table
___ (SELECT Age, MAX(BloodGlucoseRandom) AS MaxGlucose FROM Kidney GROUP BY Age) b
-- Join on Age
___
Modifica ed esegui il codice