PostgreSQL-11 partition creation issue

Hi,

I am trying to create a partition table for UNIX epoch column. Here are the details of the table. Our application is converting the date and storing the date in UNIX epoch time format.

CREATE TABLE public.oauth_server_nonce_new (
osn_id integer NOT NULL,
osn_consumer_key character varying(64) NOT NULL,
osn_token character varying(64) NOT NULL,
osn_timestamp bigint NOT NULL,
osn_nonce character varying(80) NOT NULL
) partition by to_timestamp(osn_timestamp/1000)::date;

CREATE TABLE measurement_y2016 PARTITION OF oauth_server_nonce_new FOR VALUES FROM ('2020-07-01') TO ('2020-08-01');
CREATE TABLE measurement_y2017 PARTITION OF oauth_server_nonce_new FOR VALUES FROM ('2020-08-01') TO ('2020-09-01');

Getting the following error.

ERROR: syntax error at or near "/"
LINE 7: ) partition by to_timestamp(osn_timestamp/1000)::date;

Any help is appreciated.

Regards,
Ravi
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