HI everyone, I'm trying to use sqlalchemy (0.9.10) to retrieve the number of rows of table in PostgreSQL, here a stub of the code:
import sqlalchemy from sqlalchemy import select, create_engine, MetaData, Table, Column import datetime engine = create_engine('postgresql+pg8000://postgres:password@localhost/mydb') metadata = MetaData(engine) tab = Table('test', metadata, Column('c1', sqlalchemy.INTEGER) ) tab.create() tab.insert().values(c1=123456).execute() res = select([sqlalchemy.func.count('*')], None, from_obj=[tab]).execute().fetchall() print res And here is the error I get: Traceback (most recent call last): File "C:\Users\Impara 01\Desktop\t.py", line 13, in <module> res = select([sqlalchemy.func.count('*')], None, from_obj=[tab]).execute().fetchall() File "C:\Python27\lib\site-packages\sqlalchemy\sql\base.py", line 386, in execute return e._execute_clauseelement(self, multiparams, params) File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 1868, in _execute_clauseelement return connection._execute_clauseelement(elem, multiparams, params) File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 938, in _execute_clauseelement compiled_sql, distilled_params File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 1070, in _execute_context context) File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 1271, in _handle_dbapi_exception exc_info File "C:\Python27\lib\site-packages\sqlalchemy\util\compat.py", line 199, in raise_from_cause reraise(type(exception), exception, tb=exc_tb) File "C:\Python27\lib\site-packages\sqlalchemy\engine\base.py", line 1063, in _execute_context context) File "C:\Python27\lib\site-packages\sqlalchemy\engine\default.py", line 442, in do_execute cursor.execute(statement, parameters) File "C:\Python27\lib\site-packages\pg8000\core.py", line 568, in execute self._c.execute(self, operation, args) File "C:\Python27\lib\site-packages\pg8000\core.py", line 1613, in execute self.handle_messages(cursor) File "C:\Python27\lib\site-packages\pg8000\core.py", line 1761, in handle_messages raise self.error sqlalchemy.exc.ProgrammingError: (ProgrammingError) ('ERROR', '42P18', 'could not determine data type of parameter $1') u'SELECT count(%s) AS count_1 \nFROM test' ('*',) It seems that somehow the query is not formatted correctly....any hint? Thanks in advance! -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.