See Section 11.2, “Date and Time Data Types”, for a description of the range of values each date and time type has and the valid formats in which values may be specified. Table 12.11 Date and Time Functions NameDescription ADDDATE() Add time values (intervals) to a date value ...
The DATETIME type is used for values that contain both date and time parts. MySQL retrieves and displays DATETIME values in 'YYYY-MM-DD hh:mm:ss' format. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'. The TIMESTAMP data type is used for values that c...
The DATE data type stores date and time information. Although date and time information can be represented in both CHAR and NUMBER data types, the DATE data type has special associated properties. For each DATE value, Oracle stores the following information: century, year, month, day, hour, ...
TheTIMESTAMPdata typeisusedforvaluesthat contain bothdateandtimeparts.TIMESTAMPhas a rangeof'1970-01-01 00:00:01'UTCto'2038-01-19 03:14:07'UTC. 1. 小心TIMESTAMP 的自动更新 假设一张表有 name、birthday 这些字段,这里的自动更新是指当你修改了表中 name 这个字段,但是最后发现 birthday 这个字段...
使用CHANGE old_column new_column dataType子句重命名列。语法格式如下: ALTER TABLE 表名 CHANGE 【column】 列名 新列名 新数据类型; 1. 举例: ALTER TABLE dept80 CHANGE department_name dept_name varchar(15); 1. 2. ⑷ 删除一个列 删除表中某个字段的语法格式如下: ALTER TABLE 表名 DROP 【COLUM...
数据类型(datatype) 所容许的数据的类型。每个表列都有相应的数据类型,它限制(或容许)该列中存储的数据。 行(row) 表中的一个记录。 主键(primary key)一列(或一组列),其值能够唯一区分表中每个行。 任意两行都不具有相同的主键值 每个行都必须具有一个主键值(主键列不允许NULL值) ...
The TIMESTAMP data type is used for values that contain both date and time parts. TIMESTAMP has a range of '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC. 故相关的默认值需要设置成'1000-01-01 00:00:00'到'9999-12-31 23:59:59'之间即可 ...
CURTIME()is used to automatically insert time on MySQL table field. UnlikeCURDATE()it can be used only withTIMEdatatype fields. Obviously on errors, the field will return its Zero Value. Format: HH:mm:SS Demonstration: Run the following code on your MySQL terminal. The result will clear yo...
selectdatabase(); 三.表操作 1.创建表 CREATETABLEtable_name ( field1 datatype, field2 datatype, field3 datatype ) [character set 字符集][collate 校对规则 character set 字符集 collate 校对规则 field:指定列名 datatype:指定列类型 注意:创建表时,要根据需保存的数据创建相应的列,并根据数据的类型...
-- columnN datatype, -- PRIMARY KEY(one or more columns) -- ); create table python_mysql_classes( id int UNSIGNED auto_increment PRIMARY key not null, name VARCHAR(10) ); desc python_mysql_classes; mysql表字段增删改查操作 -- 使用数据库名 ...