CODEWITHSUNDEEP
pythonmysqlmysql-python
dlyxzen
dlyxzen

Reputation: 243

Checking for empty queryset in Python/MySQLdb

I can't seem to find a simple answer for this question. I am using MySQLdb for Python and I am running a select statement, I want to check if an empty query set is returned.

get_port = db.cursor()
get_port.execute(""" SELECT port FROM nar_ports WHERE port=%s AND hostname=%s;""", (device_port,PE))

I have tried 

if not get_port:

This doesn't match. So then I tried

for result in get_port.fetchall():
    existing_port = result[0]
if not existing_port:

But it doesn't even seem to enter the loop. So then I tried to check the length

if len(get_port) == 0:

But it seems you can't run len on a sql object. So I check if the object has a none value.

if get_port = None:

But this doesn't seem to work either.

I'm certain there is a simple solution for this but I cannot seem to find it. Any help would be greatly appreciated. Thanks in advance.

cheers

Upvotes: 2

Views: 7265

Answers (1)

pydsigner
pydsigner

Reputation: 2885

It is simple, though you almost had a longer way.

if get_port.fetchone():
    do_something_here()

You could also have used

if len(get_port.fetchmany()):
    do_something_here()

But that is longer and less efficient.

Upvotes: 3

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