Postgresql - Insert into where not exists using sqlalchemy's INSERT from SELECT

Question

As pointed out here its possible to do the following with postgresql 9.1+

INSERT INTO example_table
    (id, name)
SELECT 1, 'John'
WHERE
    NOT EXISTS (
        SELECT id FROM example_table WHERE id = 1
    );

I've been having a play around with version 0.9 of sqlalchemy where they have introduced INSERT from SELECT method which should theoretically handle the above.

Is it possible and if so how? (as i want to take advantage of the result.inserted_primary_key that is not returned when using raw sql)

How can I use bindparams for the 'from_select' part as the only way I can seem to use it is when using table columns in the select.

e.g.

insrt = example_table.insert().
    from_select(['id', 'name'],
    example_table.select().
    where(~exists(select([example_table.c.id],
    example_table.c.id == 1))))

result = session.execute(insrt)

if result.is_insert:
    print 'do something with result.inserted_primary_key'

Answer 1

from sqlalchemy import *

"""
INSERT INTO example_table
    (id, name)
SELECT 1, 'John'
WHERE
    NOT EXISTS (
        SELECT id FROM example_table WHERE id = 1
    );
"""

m = MetaData()

example_table = Table("example_table", m,
                        Column('id', Integer),
                        Column('name', String)
                    )

sel = select([literal("1"), literal("John")]).where(
           ~exists([example_table.c.id]).where(example_table.c.id == 1)
      )

ins = example_table.insert().from_select(["id", "name"], sel)
print(ins)

output:

INSERT INTO example_table (id, name) SELECT :param_1 AS anon_1, :param_2 AS anon_2 
WHERE NOT (EXISTS (SELECT example_table.id 
FROM example_table 
WHERE example_table.id = :id_1))