Peewee fn.AVG() returns int, expected float-CodePudding

For some reason peewee fn.AVG() function returns int values, while it is supposed to return float.

If I execute the following raw SQL query in DB Browser:

SELECT players.name, AVG(marks.skill) FROM players 
JOIN marks ON player_id = players.id 
GROUP BY players.id;

I get the correct result:

Charname | 6.6

However, if I execute this Python code:

from peewee import *
import models

query = (
    models.Player.select(
        models.Player.name,
        fn.AVG(models.Mark.skill).alias('skill'),
    )
    .join(models.Mark, JOIN.LEFT_OUTER)
    .group_by(models.Player.id)
)

for q in query:
    print(q.name, q.skill, type(q.skill))

I get the result as truncated int:

Charname 6 int

What might be wrong?

I'm using SQLite, models.Mark.skill is an IntegerField.

CodePudding user response：

You'll want to chain .coerce(False) to the fn.AVG() - this tells Peewee that we don't want to treat the resulting aggregate as an integer (since this func is called with a single argument corresponding to an integer field):

query = (
    models.Player.select(
        models.Player.name,
        fn.AVG(models.Mark.skill).coerce(False).alias('skill'),
    )
    .join(models.Mark, JOIN.LEFT_OUTER)
    .group_by(models.Player.id)
)

Doc: http://docs.peewee-orm.com/en/latest/peewee/api.html#Function.coerce