Thanks Simon for response.
Actually column names I am getting from user interface based on user
selection that is why i want pass columns in query method dynamically. can
you suggest me how can achieve this.
On Wednesday, April 5, 2017 at 5:08:50 PM UTC+5:30, Simon King wrote:
>
> On Wed, Apr 5, 2017 at 11:10 AM, Mayank Soni <[email protected]
> <javascript:>> wrote:
> > I am trying to pass list of columns of table into query method using
> > add_columns method. Below i am mentioning code snipped.
> >
> > def LLL():
> > Base = automap_base()
> > class AAA(Base):
> > __tablename__ = 'schools_master'
> > Base.prepare(engine, reflect=True)
> > session = sessionmaker(bind=engine)
> > session = session()
> > col_name =
> >
> ['dise_code_01','district_name_02','block_name_03','cluster_name_04','village_name_05']
>
>
> >
> > q = session.query(AAA).add_columns(col_list)
> >
> > q = q.limit(100)
> >
> > for row in q:
> > print(row)
> >
> > When i execute this code it is generating error massage :
> > massage.sqlalchemy.exc.InvalidRequestError: SQL expression, column, or
> > mapped entity expected - got '['dise_code_01', 'district_name_02',
> > 'block_name_03', 'cluster_name_04', 'village_name_05']
> >
> > Please help me out from this error.
> >
>
> add_columns expects each column to be supplied as a separate argument,
> so you at least need:
>
> q = session.query(AAA).add_columns(*col_list)
>
> ...to unpack the list.
>
> Hope that helps,
>
> Simon
>
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