65.ORM查詢條件：gte,gt,lte和lt的使用

1. gte: 代表的是大於等於，英文全稱為：great than equal。舉例：找到文章id大於等於3等文章，示例代碼如下：

定義模型的示例代碼如下：

from django.db import models


class Category(models.Model):
    name = models.CharField(max_length=100)

    class Meta:
        db_table = 'category'


class Article(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField()
    category = models.ForeignKey('Category', on_delete=models.CASCADE, null=True)

    def __str__(self):
        return "<(Article: id: %s,title: %s, content: %s)>" % (self.id, self.title, self.content)

    class Meta:
        db_table = 'article'

views.py文件中視圖函數的示例代碼如下：

from .models import Article, Category
from django.http import HttpResponse


def index(request):
    # gte:查找出文章id大於等於3的文章
    articles = Article.objects.filter(id__gte=3)
    print(articles)
    print(articles.query)
    return HttpResponse("success")

打印出結果：

<QuerySet [<Article: <(Article: id: 3,title: 鋼鐵是怎樣煉成的, content: 你好)>>,
<Article: <(Article: id: 4,title: 中國吸引力, content: 精彩極了)>>]>
原生sql語句為：SELECT article.id, article.title, article.content, article.category_id FROM article WHERE article.id >= 3

2. gt:代表的是大於等於。舉例查找id大於3的文章，示例代碼如下：

from .models import Article, Category
from django.http import HttpResponse


def index(request):
    articles = Article.objects.filter(id__gt=3)
    print(articles)
    print(articles.query)
    return HttpResponse("success")

打印出結果：

<QuerySet [<Article: <(Article: id: 4,title: 中國吸引力, content: 精彩極了
)>>]>
原生sql語句：SELECT article.id, article.title, article.content, article.category_id FROM article WHERE article.id > 3

3.lte: 代表的是小於等於，舉例查找id小於等於3的文章，示例代碼如下：

from .models import Article, Category
from django.http import HttpResponse


def index(request):
    articles = Article.objects.filter(id__lte=3)
    print(articles)
    print(articles.query)
    return HttpResponse("success")

打印出結果：

<QuerySet [<Article: <(Article: id: 1,title: Hello, content: 你好)>>,
<Article: <(Article: id: 2,title: Hello World, content: 大家好)>>,
<Article: <(Article: id: 3,title: 鋼鐵是怎樣煉成的, content: 你好)>>]>
SELECT article.id, article.title, article.content, article.category_id FROM article WHERE article.id <= 3

4.lt: 代表的是小於。舉例查找id小於3的文章。示例代碼如下：

from .models import Article, Category
from django.http import HttpResponse


def index(request):
    articles = Article.objects.filter(id__lt=3)
    print(articles)
    print(articles.query)
    return HttpResponse("success")

打印出結果：

<QuerySet [<Article: <(Article: id: 1,title: Hello, content: 你好)>>, <Article: <(Article: id: 2,title: Hello World, content: 大家好)>>]>
SELECT article.id, article.title, article.content, article.category_id FROM article WHERE article.id < 3