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(NorthwindOData.Id).label("CustomCount"), NorthwindOData.personal.name.first).group_by(NorthwindOData.personal.name.first)
for instance in rs:
	print("Count: ", instance.CustomCount)
	print("personal.name.first: ", instance.personal.name.first)
	print("---------")

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

rs = session.execute(NorthwindOData_table.select().with_only_columns([func.count(NorthwindOData_table.c.Id).label("CustomCount"), NorthwindOData_table.c.personal.name.first])group_by(NorthwindOData_table.c.personal.name.first))
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(NorthwindOData.AnnualRevenue).label("CustomSum"), NorthwindOData.personal.name.first).group_by(NorthwindOData.personal.name.first)
for instance in rs:
	print("Sum: ", instance.CustomSum)
	print("personal.name.first: ", instance.personal.name.first)
	print("---------")

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

rs = session.execute(NorthwindOData_table.select().with_only_columns([func.sum(NorthwindOData_table.c.AnnualRevenue).label("CustomSum"), NorthwindOData_table.c.personal.name.first]).group_by(NorthwindOData_table.c.personal.name.first))
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(NorthwindOData.AnnualRevenue).label("CustomAvg"), NorthwindOData.personal.name.first).group_by(NorthwindOData.personal.name.first)
for instance in rs:
	print("Avg: ", instance.CustomAvg)
	print("personal.name.first: ", instance.personal.name.first)
	print("---------")

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

rs = session.execute(NorthwindOData_table.select().with_only_columns([func.avg(NorthwindOData_table.c.AnnualRevenue).label("CustomAvg"), NorthwindOData_table.c.personal.name.first]).group_by(NorthwindOData_table.c.personal.name.first))
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(NorthwindOData.AnnualRevenue).label("CustomMax"), func.min(NorthwindOData.AnnualRevenue).label("CustomMin"), NorthwindOData.personal.name.first).group_by(NorthwindOData.personal.name.first)
for instance in rs:
	print("Max: ", instance.CustomMax)
	print("Min: ", instance.CustomMin)
	print("personal.name.first: ", instance.personal.name.first)
	print("---------")

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

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