如果情况不适用于 sql 查询 python 的空结果

Question

So basically I am trying to retrieve values from a database. My if case is that if the query result which is saved in variable data is None then it should print message data not found. If the value is not none then it should print the data. My problem is that I am on purpose giving it a value which is not present in the database which means data should be null. But my if none case is not triggering. It goes directly to else. I have attached pictures down below. Apologies if this question is too basic.

Answer 1

This is because you are testing if the data variable is am instance of the None object which, from your output, it's not it's a list.

So all you need to do is to change your if statement to if not data: which will fix the problem.

Not will pass true for None, False and empty list amongst other things. see Python Truth Value Testing