Question

我需要找到具有最大fat_intake（总体fat_intake）的user_id。

数据库：

id | user_id | fat_intake 
38      1         10     
39      1         15         
40      1         30         
41      1         14         
42      2         20         
43      2         30         
44      2         50

要获取具有最大脂肪摄入量的user_id的查询是什么？

响应应为：

Output: 
  {
    "user_id": 1,
    "total_fat_count": 69
  }

我尝试过：

maxCalorie =  CalorieInfo.objects.annotate(fat_intake=Avg('fat_intake')).aggregate(Max('fat_intake'))

Answer 1

您可以这样做

[INFO] Building fake_id 1.0.0
[INFO] ------------------------------------------------------------------------
Downloading: https://repo.maven.apache.org/maven2/javax/inject/javax.inject/1/javax.inject-1.pom
Downloaded: https://repo.maven.apache.org/maven2/javax/inject/javax.inject/1/javax.inject-1.pom (612 B at 0.5 KB/sec)
[INFO] 
[INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ fake_id ---
[INFO] fake_id:fake_id:jar:1.0.0
[INFO] \- org.glassfish.jersey.containers:jersey-container-servlet:jar:2.19:compile
[INFO]    +- org.glassfish.jersey.containers:jersey-container-servlet-core:jar:2.19:compile
[INFO]    |  \- org.glassfish.hk2.external:javax.inject:jar:2.4.0-b25:compile
[INFO]    +- org.glassfish.jersey.core:jersey-common:jar:2.19:compile
[INFO]    |  +- javax.annotation:javax.annotation-api:jar:1.2:compile
[INFO]    |  +- org.glassfish.jersey.bundles.repackaged:jersey-guava:jar:2.19:compile
[INFO]    |  +- org.glassfish.hk2:hk2-api:jar:2.4.0-b25:compile
[INFO]    |  |  +- org.glassfish.hk2:hk2-utils:jar:2.4.0-b25:compile
[INFO]    |  |  \- org.glassfish.hk2.external:aopalliance-repackaged:jar:2.4.0-b25:compile
[INFO]    |  +- org.glassfish.hk2:hk2-locator:jar:2.4.0-b25:compile
[INFO]    |  |  \- org.javassist:javassist:jar:3.18.1-GA:compile
[INFO]    |  \- org.glassfish.hk2:osgi-resource-locator:jar:1.0.1:compile
[INFO]    +- org.glassfish.jersey.core:jersey-server:jar:2.19:compile
[INFO]    |  +- org.glassfish.jersey.core:jersey-client:jar:2.19:compile
[INFO]    |  +- org.glassfish.jersey.media:jersey-media-jaxb:jar:2.19:compile
[INFO]    |  \- javax.validation:validation-api:jar:1.1.0.Final:compile
[INFO]    \- javax.ws.rs:javax.ws.rs-api:jar:2.0.1:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

Answer 2

这是正确的答案，应该对您有用。

users.objects.values('user_id').annotate(total=Sum('fat_intake'))

输出为

<QuerySet [{'user_id': 1, 'total': 69}, {'user_id': 2, 'total': 100}]>

查询以获取总计django

2 个答案: