how can i compare the result of a fetchone() with a string?
this is my query and fetch PetName is a string.
cursor.execute("SELECT AnimalName FROM Animals WHERE UPPER(AnimalName) = '%s'"
max = cursor.fetchone()
the print statement and the return:
print "Animal:%s Pet:%s" % (max, PetName)
Animal: Pet: Hamster
now i want to compare the two:
if max == PetName:
match will never increment :(
i tried max but got the error:
TypeError: 'NoneType' object is unsubscriptable
any suggestions or hints?
If max is None, that means you hit the end of the result set. fetchone()
returns a tuple for each row returned.
The real problem is your query. Rewrite it like this:
cursor.execute("SELECT AnimalName FROM Animals WHERE AnimalName = %s", (PetName,)
MySQL is normally case-insensitive (depends on the default character set and
collation you have configured). But more importantly, you were not passing
parameters correctly, which is why you got None instead of a row (tuple).
I receive a error when writing the query like this:
_mysql_exceptions.ProgrammingError: (1064, "You have an error in your SQL
syntax; check the manual that corresponds to your MySQL server version for the
right syntax to use near 'Monkey's' at line 1
I have to query with the '%s', no?
You have to lose the Python % operator in your original query. Even though
MySQLdb uses %s as a parameter placeholder, it is not doing straight string
substitution. The values you pass are quoted as needed.
I'd also say, since you are only testing for the presence of that row in the
database, you can and probably should do this:
print max # the name, but not necessary to test it, the query did that
match += 1
okay i use now this query:
cursor.execute("SELECT AnimalName FROM Animals WHERE AnimalName = %s",
max is still giving a: TypeError: 'NoneType' object is unsubscriptable
the print of max is and not the string Hamster
== Hamster is still not true
is the data in my database the reason?
fetchone() returns tuples, not strings, even if you only selected a single
column. When it returns None, you've come to the end of the result set.
I recommend reading http://www.python.org/dev/peps/pep-0249/
i understand the concept of how the return of fetchone() works but shouldn't I
be able to access the first item in a tuple via tuple?
Yes, you should, unless fetchone() returned None, which it will if eventually
if you call it enough times.
Thank you. I appreciate your help!
Log in to post a comment.
Sign up for the SourceForge newsletter:
You seem to have CSS turned off.
Please don't fill out this field.