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sqlalchemy: get max/min/avg values from a table

开发者 https://www.devze.com 2023-03-29 06:28 出处:网络
I have this query: mps =( session.query(mps).filter_by(idc = int(c.idc)) .filter_by(idmp = int(m.idmp)) .group_by(func.day(mps.tschecked))

I have this query:

mps =   (
            session.query(mps)  .filter_by(idc = int(c.idc))
                                .filter_by(idmp = int(m.idmp))
                                .group_by(func.day(mps.tschecked))
        ).all()

My probl开发者_如何学Goem is, that I don't know how to extract (with sqlalchemy) the max/min/avg value from a table...

I find this: Database-Independent MAX() Function in SQLAlchemy

But I don't know where to use this func.max/min/avg...

Can someone tell me how to do this? Can you give me an example?


The following functions are available with from sqlalchemy import func:

  • func.min
  • func.max
  • func.avg

Documentation is available here.

You can use them i.e. in the query() method.

Example:

session.query(self.stats.c.ID, func.max(self.stats.c.STA_DATE))

(just like you use aggregate functions in plain SQL)


Or just use an order_by() and select the first or last element. . .

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