Derived tables

Intermediate SQL Server

Ginger Grant

Instructor

What are Derived tables?

Query which is treated like a temporary table
Always contained within the main query
They are specified in the FROM clause
Can contain intermediate calculations to be used the main query or different joins than in the main query

Derived tables in T-SQL

SELECT a.* FROM Kidney a
-- This derived table computes the Average age joined to the actual table 
JOIN (SELECT AVG(Age) AS AverageAge 
      FROM Kidney) b 
ON a.Age = b.AverageAge

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Intermediate SQL Server