mysql> drop table if exists t_user; Query OK, 0 rows affected, 1 warning (0.00 sec) 1. 2. 三、MySQL 插入数据 INSERT INTOSQL 1、字段名和值要一一对应;数量要对应,数据类型要对应 INSERT INTO table_name ( column_name1, column_name2,...column_nameN ) VALUES ( value1, value2,...value...
【说站】mysql中default的使用 1、用于设置列的默认值,如果没有为某个字段赋值,系统会自动为该字段插入默认值。 没赋值指的是,当insert插入数据时,该字段没有指明。 2、如果指定空值,则存储的最终值是空值。 实例 代码语言:javascript 代码运行次数:0 mysql>create tableuser(ageint(11)default18);QueryOK,0row...
CREATE TABLE student( id INT PRIMARY KEY, -- 主键 NAME VARCHAR(20) ) 1. 2. 3. 4. 5、自增长 -- auto_increment 作用:自动递增。 示例: CREATE TABLE student( id INT(4) ZEROFILL PRIMARY KEY AUTO_INCREMENT, -- 自增长,从0开始 ZEROFILL 零填充 NAME VARCHAR(20) ) 1. 2. 3. 4. 注意...
I seem to recall reading somewhere that InnoDB was the default table type for MySQL 5. Yet when I did a 'show table types' it indicated that MyISAM was the default type since version 3. I'm confused. I'd appreciate any clarification on this matter. ...
### MySQL Default 类型 ### 基础概念 MySQL中的`DEFAULT`类型用于指定列的默认值。当插入新记录时,如果没有为该列提供值,则系统会自动使用默认值。默认值可以是常量、...
MySQL server generates files/directories as part of various operations like CREATE TABLE, CREATE DATABASE etc. These files/directories can be read/write/executed by user running the MySQL server (e.g. mysql user in default case). However, group permission are now restricted to read/execute. Ot...
create table t9(idintunique, name varchar(16) ); insert t9 values(1,"geng"); insert t9 values(1,"yang"); -- 报错id重复 补充知识:notnull+unique的化学反应 create table t10(idintnotnull unique, name varchar(16) );id字段变成了主键:不为空且唯一 mysql> create table t10( ->idintno...
MySQL DEFAULT ConstraintThe DEFAULT constraint is used to set a default value for a column.The default value will be added to all new records, if no other value is specified.DEFAULT on CREATE TABLEThe following SQL sets a DEFAULT value for the "City" column when the "Persons" table is ...
CREATETABLEt1(iINTDEFAULT-1,cVARCHAR(10)DEFAULT'',priceDOUBLE(16,2)DEFAULT'0.00'); SERIAL DEFAULT VALUEis a special case. In the definition of an integer column, it is an alias forNOT NULL AUTO_INCREMENT UNIQUE. With one exception, the default value specified in aDEFAULTclause must be a...
for my use case, I'm evaluating if MySQL cluster could be provided in a hosting environment. It's cheaper to store data on disk than in memory. :-) Subject Views Written By Posted default storage and tablespace when creating table