sqlalchemy columns rearrange

custom_select.py

from sqlalchemy import create_engine, Column, Integer, MetaData, Table, String
from sqlalchemy.sql import select, Select, ColumnCollection


engine = create_engine('sqlite:///:memory:', echo=True)
metadata = MetaData()


class RearrangeSelect(Select):

    def reverse_columns(self):
        return self.with_only_columns(list(self.inner_columns)[::-1])

    def reorder_columns(self, *args):
        columns = ColumnCollection()

        for c in self.inner_columns:
            columns.add(c)

        query_cols = []
        for name in args:
            c = getattr(columns, name, None)
            if c is None:
                raise ValueError('Bad column name "%s"' % name)

            query_cols.append(c)

        return self.with_only_columns(query_cols)


test = Table('test', metadata,
    Column('id', Integer, primary_key=True),
    Column('name', String),  
    Column('num', Integer, default=0),  
)
metadata.create_all(engine)
statement = RearrangeSelect([test]).group_by(test.c.id)
print(statement)
print(statement.reverse_columns())
print(statement.reorder_columns('num', 'name'))
print(statement.reorder_columns('name', 'id'))

test1.py

from sqlalchemy import create_engine, Column, Integer, MetaData, Table, String
from sqlalchemy.sql import select, Select, ColumnCollection


engine = create_engine('sqlite:///:memory:', echo=True)
metadata = MetaData()



test = Table('test', metadata,
    Column('id', Integer, primary_key=True),
    Column('name', String),  
    Column('num', Integer, default=0),  
)
metadata.create_all(engine)
statement = select([test]).group_by(test.c.id)
print(statement)
cols = list(statement.inner_columns)
print(statement.with_only_columns(cols[::-1]))
print(statement.with_only_columns([cols[2], cols[0]]))
columns = ColumnCollection()

for c in cols:
    columns.add(c)

print(statement.with_only_columns([columns.name, columns.id]))