Question

I’m working on a web application in the web.py framework and need a way for web.py/python to check if the result of a sql query is empty.

Here’s my current function:

def get_hours():
    result = dbconn.query("select * from hours where date < (select max(date) from last_export) order by date DESC")
    return result

This works as expected, but I want the function to return False if the result of the query is empty. I already know that python has no way of returning how many elements there is in a iterable object(which is returned by the dbconn.query no matter if it’s empty or not), without a count for loop. Which to me wouldn’t work since i don’t want the result to be iterated BEFORE it’s returned.

Here’s an example of what I want to achieve with the function:

def get_hours():
    result = dbconn.query("select * from hours where date < (select max(date) from last_export) order by date DESC")

    if <result is empty/no rows/nothing to iterate>:
        return False

    else:
        return result

Any suggestions?

Answer 1

def get_hours():
    result = dbconn.query("select * from hours where date < (select max(date) from last_export) order by date DESC")   

    if result:
        return result
    else:
        return False

Here is very interesting answer for further details:

https://stackoverflow.com/a/2710949/492258