build generic functions for max, min

[Former user]

result of a ''select ... max(col)'' where col is a DateTime or Numeric (or may be others) does not return this type but a "simple" scalar type like unicode, int, float...

It may be specific to SQLite.

[Mike Bayer]

if anyone is interested in volunteering for this, the functions would be added to lib/sqlalchemy/sql/functions.py, unit tests in test/sql/functions.py .

FYI the current non-generic methodology is:

func.max(somecol, type_=DateTime)

hence not a bug.

[Former user]

I've just attached a patch and test. I hope it will be ok (my first patch for SA...)

Remi.

[Mike Bayer]

It looks pretty good. there's a lot of other functions that fall under this category, like "avg()", etc. but we can start with that one. will try to get it for 0.5.0.

[Former user]

Before sending the patch, I had tried to add avg also but when I tested it against a sqlite db, it raised an error (AttributeError) when trying to do A.query.avg(DateTimeColumn)...

I think that all functions that return a scalar value should fall under the same category. I've just tested sum(). Of course sum(Date) is nonsense but sum(Decimal) should return a Decimal...

[Mike Bayer]

added min, max, sum in 58c5bb7fc104da26cd1797d9680a810a3b79ab0a.

[Mike Bayer]

Removing milestone: 0.5.0 (automated comment)