查詢一個sqlite3數據庫

Question

我想寫一個程序來查詢數據庫。數據庫是golfDB，它由一個名爲玩家的表組成，其中包含5個字段：名稱（玩家名稱），totalGross（每輪總分數的總和），totalRounds（玩過的回合數），pars（製作的總數） ，小鳥（小鳥總數），我的程序需要輸出最多的球員，一個輸入球員的平均得分（totalGross/totalRounds），並按照總得分，從最低到最高排序。現在我還沒有真正用過大多數語法分析功能或者函數來計算分數，我的平均分數函數有問題，我收到了這個錯誤，我真的不確定如何修復：

Traceback (most recent call last): 
    File "/Users/tinydancer9454/Documents/python/golfDBuserInterface.py", line 46, in <module> 
    main() 
    File "/Users/tinydancer9454/Documents/python/golfDBuserInterface.py", line 40, in main 
    queryDBavgScore(cursor) 
    File "/Users/tinydancer9454/Documents/python/golfDBuserInterface.py", line 29, in queryDBavgScore 
    answer = totalGrossScore/ totalRoundsScore 
TypeError: unsupported operand type(s) for /: 'tuple' and 'tuple' 

這是我到目前爲止的代碼：

import sqlite3 

def getDBCursor(DB): 
    """obtain and return a cursor for the database DB""" 
    conn= sqlite3.connect('/Users/tinydancer9454/Documents/python/golfDB') 
    cursor= conn.cursor() 
    return cursor 

def queryDBpars(cursor): 
    """find out which player had the most pars""" 
    cursor.execute('select name from players where pars >= 0') 


def queryDBavgScore(cursor): 
    """find the average score of inputed player""" 
    player= input("Please enter the player's name: ") 
    cursor.execute('select totalGross from players where name = ?', (player,)) 
    totalGrossScore = cursor.fetchone() 
    cursor.execute('select totalRounds from players where name = ?', (player,)) 
    totalRoundsScore = cursor.fetchone() 
    answer = totalGrossScore/ totalRoundsScore 
    print('The average score for', player, 'is', answer) 

def queryDBplayers(cursor): 
    """lists the players in order of their total gross score""" 


def main(): 
    """obtain cursor and query the database: golfDB""" 
    cursor= getDBCursor('golfDB') 
    queryDBpars(cursor) 
    queryDBavgScore(cursor) 
    queryDBplayers(cursor) 
    cursor.close() 

Answer 1

的SQLite3的fetchone返回一個元組，所以你需要嘗試潛入之前得到的第一個項目，否則你就基本上可以劃分兩個元。

totalGrossScore = cursor.fetchone()[0] 
totalRoundsScore = cursor.fetchone()[0] 

在這種情況下，你的查詢只從一個字段獲取數據，但請記住，一個查詢可能返回不止一個領域，這就是爲什麼fetchone返回一個元組。