#24662: Sum() returns True/False when used with BooleanField & MySQL
-------------------------------------+-------------------------------------
Reporter: chriskief | Owner: marco-
| santamaria
Type: Bug | Status: assigned
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by jarshwah):
* stage: Unreviewed => Accepted
Comment:
SUM(bool_field) on Oracle will return 1 also, because bools in Oracle are
just a bit (1 or 0). Postgres has a specific bool type, and you can't sum
a True/False without an implicit conversion to int. This is why I say
SUM(bool) is only accidentally supported for a subset of databases. The
field type that is returned is based on the backend get_db_converters and
the actual values that come back.
Now, something needs to change here. What I would propose to do is:
1) Document that SUM(bool) is not supported in some way. Perhaps by
documenting that SUM can only be applied to numeric types.
2) Raise a warning if SUM(bool_field) is used with the suggestion to
convert it to COUNT(bool_field)
3) Begin to deprecate the ability to SUM(bool_field) (an extension of 2)
above).
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Ticket URL: <https://code.djangoproject.com/ticket/24662#comment:7>
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