我有一个 uni 的任务,我碰壁了,我似乎无法让它工作,无论我尝试什么。
因此,本次作业的重点是从 Python 访问 MySQL 数据库,以及查看和排列数据。该数据库名为 inb104,存在两个表,cars_for_sale 和 car_details。
这是我的代码
def top_N_expensive(num_of_highest):
connection = MySQLdb.connect(host='localhost', user='root', passwd='root',\
db='inb104')
cursor = connection.cursor()
sql = "SELECT cars_for_sale.make, cars_for_sale.model, +'$'+car_details.price \
FROM cars_for_sale, car_details WHERE cars_for_sale.CarId = car_details.CarId \
ORDER BY price DESC,price LIMIT " + str(num_of_highest)
cursor.execute(sql)
rows = cursor.fetchall()
for row in rows:
print row[0], row[1], row[2]
cursor.close()
connection.close()
现在,当我运行此代码时,测试用例失败,这只是其中一个测试用例,但其余的都是相同的
File "__main__", line 4, in __main__
Failed example:
top_N_expensive(10)
Expected:
VOLKSWAGEN GOLF $1300000
MERCEDES-BENZ SL $329990
BMW 3 $299990
MERCEDES-BENZ SL $249990
PORSCHE 911 $249990
MERCEDES-BENZ SL $224990
PORSCHE 911 $219990
PORSCHE 911 $190000
PORSCHE 911 $184990
BMW M5 $180000
Got:
VOLKSWAGEN GOLF 1300000.0
MERCEDES-BENZ SL 329990.0
BMW 3 299990.0
MERCEDES-BENZ SL 249990.0
PORSCHE 911 249990.0
MERCEDES-BENZ SL 224990.0
PORSCHE 911 219990.0
PORSCHE 911 190000.0
PORSCHE 911 184990.0
BMW M5 180000.0
如您所见,它失败了,因为末尾有一个零,而开头没有 $,有人知道问题所在吗?
编辑:添加此新代码后
for row in rows:
print "%s %s $%d" % (row[0], row[1], row[2])
我得到了 3/4 个测试用例通过,我不知道为什么最后一个没有通过,但这是测试用例转储
Trying:
top_N_expensive(10)
Expecting:
VOLKSWAGEN GOLF $1300000
MERCEDES-BENZ SL $329990
BMW 3 $299990
MERCEDES-BENZ SL $249990
PORSCHE 911 $249990
MERCEDES-BENZ SL $224990
PORSCHE 911 $219990
PORSCHE 911 $190000
PORSCHE 911 $184990
BMW M5 $180000
Warning (from warnings module):
File "Z:\Documents\top_N_expensive.py", line 82
cursor.execute(sql)
Warning: Truncated incorrect DOUBLE value: '$'
ok
Trying:
top_N_expensive(15)
Expecting:
VOLKSWAGEN GOLF $1300000
MERCEDES-BENZ SL $329990
BMW 3 $299990
MERCEDES-BENZ SL $249990
PORSCHE 911 $249990
MERCEDES-BENZ SL $224990
PORSCHE 911 $219990
PORSCHE 911 $190000
PORSCHE 911 $184990
BMW M5 $180000
MERCEDES-BENZ E55 $179990
MERCEDES-BENZ CLS $179990
PORSCHE 911 $165000
PORSCHE 911 $164900
PORSCHE 911 $161950
**********************************************************************
File "__main__", line 17, in __main__
Failed example:
top_N_expensive(15)
Expected:
VOLKSWAGEN GOLF $1300000
MERCEDES-BENZ SL $329990
BMW 3 $299990
MERCEDES-BENZ SL $249990
PORSCHE 911 $249990
MERCEDES-BENZ SL $224990
PORSCHE 911 $219990
PORSCHE 911 $190000
PORSCHE 911 $184990
BMW M5 $180000
MERCEDES-BENZ E55 $179990
MERCEDES-BENZ CLS $179990
PORSCHE 911 $165000
PORSCHE 911 $164900
PORSCHE 911 $161950
Got:
VOLKSWAGEN GOLF $1300000
MERCEDES-BENZ SL $329990
BMW 3 $299990
MERCEDES-BENZ SL $249990
PORSCHE 911 $249990
MERCEDES-BENZ SL $224990
PORSCHE 911 $219990
PORSCHE 911 $190000
PORSCHE 911 $184990
BMW M5 $180000
MERCEDES-BENZ CLS $179990
MERCEDES-BENZ E55 $179990
PORSCHE 911 $165000
PORSCHE 911 $164900
PORSCHE 911 $161950
Trying:
top_N_expensive(1)
Expecting:
VOLKSWAGEN GOLF $1300000
ok
Trying:
top_N_expensive(0)
Expecting nothing
ok
1 items had no tests:
__main__.top_N_expensive
**********************************************************************
1 items had failures:
1 of 4 in __main__
4 tests in 2 items.
3 passed and 1 failed.
***Test Failed*** 1 failures.
所以,不知道为什么现在失败了,很奇怪。
这是更新的查询
def top_N_expensive(num_of_highest):
connection = MySQLdb.connect(host='localhost', user='root', passwd='root',\
db='inb104')
cursor = connection.cursor()
sql = "SELECT cars_for_sale.make, cars_for_sale.model, +'$'+car_details.price \
FROM cars_for_sale, car_details WHERE cars_for_sale.CarId = car_details.CarId \
ORDER BY price DESC, make, model DESC" + str(num_of_highest)
cursor.execute(sql)
rows = cursor.fetchall()
for row in rows:
print "%s %s $%d" % (row[0], row[1], row[2])
cursor.close()
connection.close()
测试用例
Trying:
top_N_expensive(10)
Expecting:
VOLKSWAGEN GOLF $1300000
MERCEDES-BENZ SL $329990
BMW 3 $299990
MERCEDES-BENZ SL $249990
PORSCHE 911 $249990
MERCEDES-BENZ SL $224990
PORSCHE 911 $219990
PORSCHE 911 $190000
PORSCHE 911 $184990
BMW M5 $180000
**********************************************************************
File "__main__", line 4, in __main__
Failed example:
top_N_expensive(10)
Exception raised:
Traceback (most recent call last):
File "C:\Program Files\Python27\lib\doctest.py", line 1254, in __run
compileflags, 1) in test.globs
File "<doctest __main__[0]>", line 1, in <module>
top_N_expensive(10)
File "Z:\Documentstop_N_expensive.py", line 82, in top_N_expensive
cursor.execute(sql)
File "C:\Program Files\Python27\lib\site-packages\MySQLdb\cursors.py", line 174, in execute
self.errorhandler(self, exc, value)
File "C:\Program Files\Python27\lib\site-packages\MySQLdb\connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
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 'DESC10' at line 1")