search
HomeDatabaseMysql TutorialHow to use Mysql subquery keywords

1. all

1.1 Format

How to use Mysql subquery keywords

1.2 Features

all: If compared with all values ​​returned by the subquery, it is true. Return true

all can be used in combination with =,>=,>,, which respectively means equal to, greater than or equal to, greater than, less than, less than or equal to, not equal to All the data

is greater than all, which means that the value in the specified column must be greater than every value in the subquery set, that is, it must be greater than the maximum value of the subquery set; if it is less than, it is less than the minimum value in the subquery set. value.

1.3 Operation

How to use Mysql subquery keywords

2. any (some)

1.1 Format

How to use Mysql subquery keywords

1.2 Features

  • any: If compared with all values ​​returned by the subquery, true will be returned

  • ##any can be used with =,> =,>, are used in combination to represent equal to, greater than or equal to, greater than, less than, less than or equal to, and not equal to any of the data

  • Greater than any means that the value in the specified column must be greater than any value in the subquery set, that is, it must be greater than the minimum value of the subquery set; the same is true for others

  • some can understand Alias ​​for any

1.3 Operation

How to use Mysql subquery keywords##3. in

1.1 Format

How to use Mysql subquery keywords1.2 Features

    in is used to determine whether the value of a record is in the specified collection
  • Add not in front of the in keyword to reverse the condition
  • 1.3 Operation

How to use Mysql subquery keywords4. exist

1.1 Format

How to use Mysql subquery keywords1.2 Features

    If this subquery "has data results" (returns at least one row of data), then The EXISTS() result is: true, and the outer query is executed
  • If the subquery has "no data result" (no data is returned), the EXISTS() result is: false , the outer query is not executed
  • The subquery after EXISTS does not return any actual data, only true or false, and when true is returned, the where condition is established
  • Note: The EXISTS keyword is more efficient than the IN keyword. Therefore, in actual development, especially when the amount of data is large, it is recommended to use the EXISTS keyword
  • 1.3 Operation

How to use Mysql subquery keywords1.4 Explanation

When the outer query is queried, the outer query will be executed row by row. When the first row is executed, it will be judged whether the subquery is If it is true, this row of data is found, and then the second row of data is queried. . . Repeat this.

The above is the detailed content of How to use Mysql subquery keywords. For more information, please follow other related articles on the PHP Chinese website!

Statement
This article is reproduced at:亿速云. If there is any infringement, please contact admin@php.cn delete
图文详解mysql架构原理图文详解mysql架构原理May 17, 2022 pm 05:54 PM

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于架构原理的相关内容,MySQL Server架构自顶向下大致可以分网络连接层、服务层、存储引擎层和系统文件层,下面一起来看一下,希望对大家有帮助。

mysql的msi与zip版本有什么区别mysql的msi与zip版本有什么区别May 16, 2022 pm 04:33 PM

mysql的msi与zip版本的区别:1、zip包含的安装程序是一种主动安装,而msi包含的是被installer所用的安装文件以提交请求的方式安装;2、zip是一种数据压缩和文档存储的文件格式,msi是微软格式的安装包。

mysql怎么去掉第一个字符mysql怎么去掉第一个字符May 19, 2022 am 10:21 AM

方法:1、利用right函数,语法为“update 表名 set 指定字段 = right(指定字段, length(指定字段)-1)...”;2、利用substring函数,语法为“select substring(指定字段,2)..”。

mysql怎么替换换行符mysql怎么替换换行符Apr 18, 2022 pm 03:14 PM

在mysql中,可以利用char()和REPLACE()函数来替换换行符;REPLACE()函数可以用新字符串替换列中的换行符,而换行符可使用“char(13)”来表示,语法为“replace(字段名,char(13),'新字符串') ”。

mysql怎么将varchar转换为int类型mysql怎么将varchar转换为int类型May 12, 2022 pm 04:51 PM

转换方法:1、利用cast函数,语法“select * from 表名 order by cast(字段名 as SIGNED)”;2、利用“select * from 表名 order by CONVERT(字段名,SIGNED)”语句。

MySQL复制技术之异步复制和半同步复制MySQL复制技术之异步复制和半同步复制Apr 25, 2022 pm 07:21 PM

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于MySQL复制技术的相关问题,包括了异步复制、半同步复制等等内容,下面一起来看一下,希望对大家有帮助。

mysql怎么判断是否是数字类型mysql怎么判断是否是数字类型May 16, 2022 am 10:09 AM

在mysql中,可以利用REGEXP运算符判断数据是否是数字类型,语法为“String REGEXP '[^0-9.]'”;该运算符是正则表达式的缩写,若数据字符中含有数字时,返回的结果是true,反之返回的结果是false。

带你把MySQL索引吃透了带你把MySQL索引吃透了Apr 22, 2022 am 11:48 AM

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了mysql高级篇的一些问题,包括了索引是什么、索引底层实现等等问题,下面一起来看一下,希望对大家有帮助。

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Tools

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.