python - How can I bind a list to a parameter in a custom query in sqlalchemy?

Question

I am using this sql for performance reason

 sql_tmpl = """delete from Data where id_data in (:iddata) """
 params = {  
                    'iddata':[1, 2,3 4],
                    }
 # session is a session object from   sqlalchemy
 self.session.execute(text(sql_tmpl), params)     

However I got an exception

NotSupportedError: (NotSupportedError) ('Python type list not supported.  param=1', 'HY097') 

Is there any workaround that can allow me to bind a list to the parameter of the 'in' clause?

question from:https://stackoverflow.com/questions/13190392/how-can-i-bind-a-list-to-a-parameter-in-a-custom-query-in-sqlalchemy

Answer 1

New answer to an old question because it seems like some of the underlying functionality has changed since this question/accepted answer were first posted (as alluded to by @vicvicvic in @Gary's answer, but I feel it should be an answer for better visibility).

psycopg2 now supports type adaptation, which allows, among other things, the ability to pass a list into a single parameterized value in the query. This also works in SQLAlchemy, at the very least for raw-SQL-esque queries to a postgresql database (I don't have access to other database types, so I don't know if sqlalchemy will respect this convention for other databases, but my inclination^{citation needed} is that it will work).

some_ids = [1, 2, 3, 4]
query = "SELECT * FROM my_table t WHERE t.id = ANY(:ids);"
conn.execute(sqlalchemy.text(query), ids=some_ids)
## runs just fine

I found that without the wrapper call to sqlalchemy.text, it gave a ProgrammingError: syntax error at or near ":".