fetchone() compare to a string

[damaex]

Hi!

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'"
% (PetName.upper()))

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 +=1

match will never increment :(

i tried max but got the error:

TypeError: 'NoneType' object is unsubscriptable

any suggestions or hints?

[Andy Dustman]

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).

[damaex]

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?

[Andy Dustman]

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.

[Andy Dustman]

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:

If max:
    print max[0] # the name, but not necessary to test it, the query did that
    match += 1

[damaex]

okay i use now this query:

cursor.execute("SELECT AnimalName FROM Animals WHERE AnimalName = %s",
(PetName.upper(),))

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?

[Andy Dustman]

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/

[damaex]

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?

[Andy Dustman]

Yes, you should, unless fetchone() returned None, which it will if eventually
if you call it enough times.

[damaex]

Thank you. I appreciate your help!