SQLAlchemy - check if query found any results

Question

How can I check if a query found any results?

result = db.engine.execute(sql, id=foo)
// check if result has rows ...
for row in result:
  ...

Tried this:

if result is None:
    print("reuslt is None!")

and checked length:

print("result len", len(result))

Answer 1

all() may be quite slow for some databases, count() is better but first() is even faster for large databases and complex queries. For example:

x = db.session.query(Post).filter(Post.read==True).first() is not None

Answer 2

len is the better way. You were near:

print("result len", len(result.all()))

You cant access to a BaseQuery len if you dont get all of its elements.

Compare result with None is ok if you want to know if its empty.