mysql 查找重复姓名且年龄最大的列表
1 |
|
这里找到count 重复的数据
下面接着找 count 最大,切age 最大且相同的数据
1 |
|
为什么少了一条 dtest ,dtest的数据和ctest在count和age上是一样的?
求指教!谢谢
回复讨论(解决方案)
第二式有 group by count,那么 count 相同的肯定在一组了
既然
| 2 | ctest | 43 |
| 2 | dtest | 43 |
在一组,那自然只能出现一个了
所以分组条件应加上 age,即 group by count,age
1 |
|
这个结果不对吧?
预期的结果应该是:
1 |
|
select count,name,age from ( select count(*) as count ,name,sum(age) as age from t1 group b
name order by count desc ,age desc ) as tmp group by count, name order by count desc ,age desc;
1 |
|
group by count,name 这样找不到 count=2且age最大的数据和count=1且age最大的数据了~
1 |
|
这种预期的结果,能在一条sql里体现出来么?
求指教
感觉效率应该不是很高,虽然可以做出来
1 |
|
select tmp1.count,tmp1.age from (select count,max(age) as age from ( select count(*) as count ,name,sum(age) as age from t1 group by
name order by count desc ,age desc ) as tmp group by count order by count desc ,age desc) as tempd,( select count(*) as count ,name,sum(age) as age from t1 group by
name order by count desc ,age desc ) as tmp1 where tmp1.count=tempd.count and tmp1.age=tempd.age count order by tmp1.count desc ,tmp1.age desc;
非常感谢版主

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics





Alipay PHP...

Session hijacking can be achieved through the following steps: 1. Obtain the session ID, 2. Use the session ID, 3. Keep the session active. The methods to prevent session hijacking in PHP include: 1. Use the session_regenerate_id() function to regenerate the session ID, 2. Store session data through the database, 3. Ensure that all session data is transmitted through HTTPS.

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

The application of SOLID principle in PHP development includes: 1. Single responsibility principle (SRP): Each class is responsible for only one function. 2. Open and close principle (OCP): Changes are achieved through extension rather than modification. 3. Lisch's Substitution Principle (LSP): Subclasses can replace base classes without affecting program accuracy. 4. Interface isolation principle (ISP): Use fine-grained interfaces to avoid dependencies and unused methods. 5. Dependency inversion principle (DIP): High and low-level modules rely on abstraction and are implemented through dependency injection.

How to automatically set the permissions of unixsocket after the system restarts. Every time the system restarts, we need to execute the following command to modify the permissions of unixsocket: sudo...

How to debug CLI mode in PHPStorm? When developing with PHPStorm, sometimes we need to debug PHP in command line interface (CLI) mode...

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

Sending JSON data using PHP's cURL library In PHP development, it is often necessary to interact with external APIs. One of the common ways is to use cURL library to send POST�...
