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## Generalized Projection Operation, Aggregation Operation in Python

### Let’s consider the following table and understand these operations with examples.

R1 :    FACULTY-1

 FNo FName DNo Qual Salary 22 Riya 21 Ph.D 55000 24 Priya 22 M. Tech 50000 25 Zayn 22 M. Tech 42000 27 Harry 23 M. Tech 28000 30 Sia 23 M. Tech 32000 33 Max 24 Ph.D 53000 35 Fred 24 Ph.D 52000 37 Diva 25 M. Tech 26000 39 Ben 25 M. Tech 24000 40 Trent 25 M. Tech 34000

### Generalized Projection Operation ( P ) :

This operation allows arithmetic operations or string operations in the attribute list of projection operations.

Example-1 :  Find the list of FName having PhD degree and their 10 %  of Salaries.

P FName, Salary ¸ 10  (sQual = ‘PhD’ (Faculty-1)

Output :

 FName 10% x Salary Riya 5500 Max 5300 Fred 5200

### Aggregation Operation : (   )

Aggregate Function takes a collection of values and returns a single value as a result.

Example-2 :  Find the sum of the salaries of all the faculty.

(Faculty-1)

sum(Salary)

Output :                       396000

Example-3 :  Find the average of the salaries of all the faculty

(Faculty-1)

average(Salary)

Output :                            39600