How to Insert into with postgresql and JSONB
Quickly did lots of testing and i got what you wanted.

INSERT INTO product(data1, job_id)
SELECT json_build_object('__COD__',data2-&gt;&gt;'cod','__PAGE__',data2-&gt;&gt;'page') data1, job_id FROM product_temp;


Your data1 is one column. Tested with PostgreSQL 9.5