On Fri, 21 Oct 2022 at 09:23, PG Doc comments form <nore...@postgresql.org> wrote: > > The following documentation comment has been logged on the website: > > Page: https://www.postgresql.org/docs/15/sql-comment.html > Description: > > I've recently been converting some DML which was intended for BigQuery to > use PostgreSQL 14. Using a python client (using sqlalchemy and the > postgresql+psycopg2 driver), I had successfully created a table and was > trying to add comments to the columns. All of this was previously done in a > single statement on BigQuery, but requires separate CREATE TABLE and COMMENT > ON COLUMN statements for PostgreSQL. > > For one of the comment statements I received this error: "dict is not a > sequence". It turns out the culprit was that one of the comments had a '%' > character. I'm not familiar with restrictions on strings in PostgreSQL, but > it would be helpful to have a list of these.
This is likely not coming from PostgreSQL. Psycopg uses `%s` as a placeholder. As a consequence, if you want to pass a literal `%`, you have to escape it at `%%`. See documentation at https://www.psycopg.org/docs/usage.html#passing-parameters-to-sql-queries -- Daniele
