Question

我正在尝试创建一个返回结果的查询，不包括列中的4个特定值。

这是我的代码：

SELECT CustomerID,
       ContactName,
       Country
FROM   Customers
WHERE  CustomerID IN (SELECT CustomerID
                      FROM   Customers
                      WHERE  (Country <> ('UK')('Australia')('Canada')));

如果我只排除一个国家而不是多个国家，则此方法有效。

提前感谢您提供的任何帮助。

Answer 1

使用ValueError: attempted relative import beyond top-level package运算符

列表应该用逗号分隔，不需要为列表中的每个值打开/关闭括号。此外，您不需要NOT IN只需添加过滤器sub-query子句

Where

确保您未在列表中传递任何SELECT CustomerID, ContactName, Country FROM Customers WHERE Country NOT IN ( 'USA', 'UK', 'Australia', 'Canada' )值，因为NULL在列表中存在NOT IN值时失败

Answer 2

import pygame
import random
import sys
pygame.mixer.pre_init(44100, -16, 2, 2048)

pygame.init()

pygame.mixer.music.load('grand-metropolis.mp3')
pygame.mixer.music.play()
pygame.mixer.music.set_volume(0.7)


SCR_WID, SCR_HEI = 640, 480
screen = pygame.display.set_mode((SCR_WID,SCR_HEI), 0, 16)
pygame.display.set_caption("Ever Emerald")
font = pygame.font.SysFont("white", 32)

bg = pygame.image.load("sddefault.jpg")


class Player():
        def __init__(self, SCR_WID, SCR_HEI,):

                self.x, self.y = SCR_WID, SCR_HEI/2 
                self.speed = 3
                self.padWid, self.padHei = 8, 64
                self.score = 0
                self.scoreFont = pygame.font.Font("imagine_font.ttf", 64)

        def scoring(self, screen, cord, winner):

                scoreBlit = self.scoreFont.render(str(self.score), 1, (255, 255, 255))
                screen.blit(scoreBlit, (cord, 16))

                if self.score == 10:
                        print (winner) 
                        exit()

        def movement(self, up, down):

                keys = pygame.key.get_pressed()
                if keys[up]: 
                        self.y -= self.speed
                elif keys[down]:
                        self.y += self.speed

                if self.y <= 0:
                        self.y = 0
                elif self.y >= SCR_HEI-64:
                        self.y = SCR_HEI-64

        def draw(self, screen):
                pygame.draw.rect(screen, (255, 255, 255), (self.x, self.y, self.padWid, self.padHei))
                screen.blit(bg, (640,380))

Answer 3

您可以考虑在特殊表格中定义排除的国家/地区（例如ExcludedCountry）。这会将您的数据（排除的国家/地区）与您的逻辑（选择不在排除国家/地区的客户）分开。在这种情况下，您的查询可能如下所示：

select CustomerID, ContactName, Country 
from Customers C
    left join ExcludedCountry EC ON EC.Name = C.CustomerID 
where CustomerID IS NOT NULL

或

-- may be faster than above
select CustomerID, ContactName, Country 
from Customers C
where not exists (
    select 1 
    from ExcludedCountry EC 
    where EC.Name = C.CustomerID)

此解决方案的优点是可以更轻松地管理您排除的项目。

使用＆lt;＆gt;排除多个值

3 个答案: