MySQL的常用数据类型包括:Number/Date/String,而String类型中又包含了 Char/Varchar/Binary/blob/text 等长度不同的简单数据类型,有时我们需要对数据做更细致的管理,比如枚举和集合,就需要复合类型ENUM和SET了。 ENUM 枚举类型 ENUM适合于只能在一组固定值中选一个的场景,比如性别只能为男或者女。 ENUM的优势在于:...
Namespace:MySql.Data.MySqlClient Assembly: MySql.Data.dll Version: 9.3.0 Syntax publicenumMySqlDbType Fields NameDescription Binary Fixed length binary string. Bit Bit-field data type Blob A binary column with a maximum length of 65535 (2^16 - 1) bytes. ...
select settype,settype+0,bin(settype+0),enumtype,enumtype+0,bin(enumtype+0) from setenum; 1. select * from setenum where settype=33; 1. select * from setenum where enumtype=2; 1. –不支持二进制查询 mysql> select * from setenum where settype=b'010011'; Empty set mysql> select...
mysql> INSERT INTO t (numbers) VALUES(2),('2'),('3'); mysql> SELECT * FROM t; +---+ | numbers | +---+ | 1 | | 2 | | 2 | +---+ To determine all possible values for an ENUM column, use SHOW COLUMNS FROM tbl_name LIKE 'enum_col' and parse the ENUM definition in ...
-- MySQL 会自动类型转换,+、-、\*、/ 会将数据转换成数值,普通字符串转换为数值 0 select gender + 0 from tb_demo; mysql> select gender + 0 from tb_demo; +---+ | gender + 0 | +---+ | 1 | | 2 | +---+ -- 可直接插入数值数据 insert into tb_demo(gender) values (1); mysq...
root@localhost : test 11:22:53> INSERT INTO mysqlops_enum(ID,Job_type,Work_City) VALUES(3,‘Other’,NULL); ERROR 1048 (23000): Column ‘Work_City’ cannot be null 测试第一个枚举类型字段Job_type是否可以存储空白值: root@localhost : test 11:22:59> INSERT INTO mysqlops_enum(ID,Job_ty...
MySQL数据库:5.5.15-log InnoDB存储引擎:plugin-InnoDB 1.1.8 (二)测试数据准备 详见之前的文章 知乎用户www.zhihu.com/people/amygo-8/posts (三)枚举类型ENUM字段DDL操作 a)增加枚举类型字段定义的默认值属性 root@localhost : mysqlops 02:35:51> ALTER TABLE mysqlops_set_enum MODIFY Work_Option enum...
MySQL数据库之枚举数据类型ENUM的DDL变更测试 针对四种数据类型:布尔类型BOOL或称布尔类型BOOLEAN、微整型TINYTINT、枚举类型ENUM、集合类型SET,我们已经分多篇文章篇幅Amygo的往期文章主页给出详细的介绍与功能测试数据,接下来我们深入介绍枚举类型EUNM和集合类型SET。测试基于InnoDB存储引擎上,对MySQL数据库枚举类型ENUM的字...
mysql>CREATE DATABASE ado; To run the attached files in the ADO/script-unit test framework, drop the attached script file in the 'level 0' dir, and the data file in the common dir. Open script-unit, drag the script file to the work area, highlight and run it. What the test does...
-> ADD COLUMN `type` tinyint NOT NULL DEFAULT 0 COMMENT '反应类型' AFTER `i ntegral`; Query OK, 115597 rows affected (0.54 sec) Records: 115597 Duplicates: 0 Warnings: 0 mysql> select concat(truncate(sum(data_length)/1024/1024,3),'MB') as data_size, ...