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pythonpostgresqlsqlalchemy

Getting COUNT from sqlalchemy

I have:

res = db.engine.execute('select count(id) from sometable')

The returned object is sqlalchemy.engine.result.ResultProxy.

How do I get count value from res?

Res is not accessed by index but I have figured this out as:

count=None
for i in res:
    count = res[0]
    break

There must be an easier way right? What is it? I didn't discover it yet. Note: The db is a postgres db.

Solution

  • While the other answers work, SQLAlchemy provides a shortcut for scalar queries as ResultProxy.scalar():

    count = db.engine.execute('select count(id) from sometable').scalar()

    scalar() fetches the first column of the first row and closes the result set, or returns None if no row is present. There's also Query.scalar(), if using the Query API.