Re: [google-appengine] Re: is there any max() function available in appengine datastore to find max of selected records

[Ulrich]

Max wrote:
Order by salary means an extra index will be built over this field,
which will affect your write speed.

Use a global variable to store max(salary)
  
If you store this global variable in the datastore and have a high 
number of inserts, you have to update this global variable too often and 
it will not work without some kind of sharding.

-Ulrich
On Mar 15, 10:12 am, Takashi Matsuo <matsuo.taka...@gmail.com> wrote:
  
Hi,

Perhaps you can order by salary property descending, and just get the
first one, for getting max value.

max_salaried_employee = Employee.all().order("-salary").get()
max_salary = max_salaried_employee.salary

hope this helps

--
Takashi Matsuo
Kay's daddy

On Mon, Mar 15, 2010 at 11:00 AM, Greg <g.fawc...@gmail.com> wrote:
    
On Mar 14, 3:48 am, pyrocks <kiranbe...@gmail.com> wrote:
      
here shall we have any max() function available like in oracle to find
max salaried employee.
        
In a word, no. You need to store the maximum salary in the datastore,
and every time time a salary changes check to see if it exceeds the
maximum, and update it if so.
      
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