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use truediv for /, floordiv for // regarding numeric results

See original GitHub issue

I have the following example:

from sqlalchemy import Column, Integer, MetaData, Table, select

metadata = MetaData()
test = Table("test", metadata, Column("id", Integer))
query = select(columns=[(test.c.id / 2).label("half_id")])
print("the type of the 'half_id' column is", query.c.half_id.type)

query = select(columns=[(test.c.id / 2.0).label("half_id")])
print("the type of the 'half_id' column is", query.c.half_id.type)

This prints INTEGER and FLOAT. The latter is correct, but the former is incorrect.

Dividing 1 by 2 via / gives me 0.5 in MariaDB and Oracle and 0 in Postgres and MSSQL.

I was expecting column type derivation to follow the Python 3 rules in this case: / is a floating point division.

Issue Analytics

State:
Created 4 years ago
Comments:18 (11 by maintainers)

Top GitHub Comments

1reaction

zzzeekcommented, Dec 8, 2021

2.0 will resolve the issue completely including that it will render CAST / FLOOR on individual dialects as appropriate so that both / and // act as closely to Python as possible.

0reactions

sqla-testercommented, Dec 8, 2021

Mike Bayer has proposed a fix for this issue in the main branch:

consider truediv as truediv; support floordiv operator https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/3355

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