[Sqlalchemy-tickets] Issue #3049: support range specificaiton in window function (zzzeek/sqlalchemy)

[Mike B. <iss...@bi...>]

New issue 3049: support range specificaiton in window function
https://bitbucket.org/zzzeek/sqlalchemy/issue/3049/support-range-specificaiton-in-window

Mike Bayer:

e.g.


```
#!sql

SELECT func(x) OVER (ORDER BY x RANGE BETWEEN UNBOUNDED PRECEDING AND 10 FOLLOWING)
```

see the syntax [here](http://www.postgresql.org/docs/9.1/static/sql-expressions.html#SYNTAX-WINDOW-FUNCTIONS) and [here](http://tapoueh.org/blog/2013/08/20-Window-Functions), also might think of having the named window function.

so for this we have the option for strings:

    func.foo(x).over(frame="RANGE BETWEEN UNBOUNDED PRECEDING AND 10 FOLLOWING)

or maybe an elaborate generative thing

    func.foo(x).over().rows(start="unbounded preceding", end="current row")