Certain aggregate functions can also be used within SQLAlchemy by using the func module.

To import this module, execute:

from sqlalchemy.sql import func

Once func is imported, the following aggregate functions are available:

COUNT

The following example counts the number of records in a set of groups using the session object's query() method.

rs = session.query(func.count(Employee.EmployeeId).label("CustomCount"), Employee.FirstName).group_by(Employee.FirstName)
for instance in rs:
	print("Count: ", instance.CustomCount)
	print("FirstName: ", instance.FirstName)
	print("---------")

You can also execute COUNT using the session object's execute() method:

rs = session.execute(Employee_table.select().with_only_columns([func.count(Employee_table.c.EmployeeId).label("CustomCount"), Employee_table.c.FirstName])group_by(Employee_table.c.FirstName))
for instance in rs:

SUM

This example calculates the cumulative amount of a numeric column in a set of groups.

rs = session.query(func.sum(Employee.AnnualRevenue).label("CustomSum"), Employee.FirstName).group_by(Employee.FirstName)
for instance in rs:
	print("Sum: ", instance.CustomSum)
	print("FirstName: ", instance.FirstName)
	print("---------")

You can also invoke SUM using the session object's execute() method.

rs = session.execute(Employee_table.select().with_only_columns([func.sum(Employee_table.c.AnnualRevenue).label("CustomSum"), Employee_table.c.FirstName]).group_by(Employee_table.c.FirstName))
for instance in rs:

AVG

This example uses the session object's query() method to calculate the average amount of a numeric column in a set of groups:

rs = session.query(func.avg(Employee.AnnualRevenue).label("CustomAvg"), Employee.FirstName).group_by(Employee.FirstName)
for instance in rs:
	print("Avg: ", instance.CustomAvg)
	print("FirstName: ", instance.FirstName)
	print("---------")

You can also use the session object's execute() method to invoke AVG:

rs = session.execute(Employee_table.select().with_only_columns([func.avg(Employee_table.c.AnnualRevenue).label("CustomAvg"), Employee_table.c.FirstName]).group_by(Employee_table.c.FirstName))
for instance in rs:

MAX and MIN

This example finds the maximum value and minimum value of a numeric column in a set of groups.

rs = session.query(func.max(Employee.AnnualRevenue).label("CustomMax"), func.min(Employee.AnnualRevenue).label("CustomMin"), Employee.FirstName).group_by(Employee.FirstName)
for instance in rs:
	print("Max: ", instance.CustomMax)
	print("Min: ", instance.CustomMin)
	print("FirstName: ", instance.FirstName)
	print("---------")

You can also use the session object's execute() method to invoke MAX and MIN:

rs = session.execute(Employee_table.select().with_only_columns([func.max(Employee_table.c.AnnualRevenue).label("CustomMax"), func.min(Employee_table.c.AnnualRevenue).label("CustomMin"), Employee_table.c.FirstName]).group_by(Employee_table.c.FirstName))
for instance in rs: