The most comprehensive set of advanced features, management tools and technical support to achieve the highest levels of MySQL scalability, security, reliability, and uptime. Learn More » MySQL for OEM/ISV Over 2000 ISVs, OEMs, and VARs rely on MySQL as their products' embedded database to...
mysql> select * from tbl_emp a left join tbl_dept b on a.deptId = where is null; +---+---+---+---+---+---+ | id | NAME | deptId | id | deptName | locAdd | +---+---+---+---+---+---+ | 8 | s9 | 51 | NULL | NULL | NULL | +---+---+---+---...
SQL分类1) DDL(Data Definition Language)数据定义语言 用来定义数据库对象:数据库,表,列等。关键字:create, drop,alter 等 2) DML(Data Manipulation Language)数据操作语言 用来对数据库中表的数据进行增删改。关键字:insert, delete, update 等 3) DQL(Data Query Language)数据查询语言 用来查询数据库中表的...
SQL, which stands forStructured Query Language, is a programming language that’s used to retrieve, update, delete, and otherwise manipulate data in relational databases. MySQL is officially pronounced “My ess-cue-el,” but “my sequel” is a common variation. As the name suggests, MySQL is...
SQL:用来管理数据的语言。结构化查询语言(SQL,Structured Query Language) 主键:唯一地标识表中的某一条记录,不能空,不能重复 4.2、登录数据库 *连接本地数据库时需要启动服务 4.3、创建数据库 4.4、创建表 列的类型: 数字类型 整数: tinyint、smallint、mediumint、int、bigint 浮点数: float、double、real、de...
set_external_language() : dd::Function_impl, dd::Library_impl, dd::Procedure_impl, dd::Routine, dd::Routine_impl set_external_program_handle() : sp_head set_external_table_offload_error() : handler set_external_user_ptr() : Security_context set_factor() : Multi_factor_auth_info set...
The new GTID format is UUID:TAG:NUMBER, where TAG is a string of up to 8 characters, which is enabled by setting the value of the gtid_next system variable to AUTOMATIC:TAG, added in this release (see the description of the variable for tag format and other information). This tag pers...
结构化查询语言(Structured Query Language),简称SQL,是数据库的标准查询语言。可以通过DBMS对数据库进行定义数据,操纵数据,查询数据,数据控制等 1、数据定义语言 (DDL) Data Dafinitaon Language 如创建表 create 删除表 drop 修改表 alter 清空表 truncate,彻底清空,无法找回 show databases; # 查看所有数据库: sh...
MySQL Server, the world's most popular open source database, and MySQL Cluster, a real-time, open source transactional database. C++11.4k4k Repositories Type Language Sort mysql-shell-pluginsPublic Plugins for the MySQL Shell TypeScript831739(1 issue needs help)0UpdatedMay 28, 2025 ...
MySQL UTF-8 is actually a partial implementation of the full UTF-8 character set.Specifically, MySQL UTF-8 encoding uses a maximum of 3 bytes, whereas 4 bytes are required for encoding the full UTF-8 character set. This is fine for all language characters, but if you need to support ast...