MySQL中DATETIME和TIMESTAMP的区别 先Copy一份文档给大家看: DateTime A date and time combination. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'. MySQL displays DATETIME values in 'YYYY-MM-DD HH:MM:SS' format, but allow
MySQL中DATETIME和TIMESTAMP的区别先Copy一份文档给大家看:
DateTime
A date and time combination. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'.
MySQL displays DATETIME values in 'YYYY-MM-DD HH:MM:SS' format, but allows you to assign values to DATETIME columns using either strings or numbers.
TimeStamp
A timestamp. The range is '1970-01-01 00:00:00' to partway through the year 2037.
A TIMESTAMP column is useful for recording the date and time of an INSERT or UPDATE operation.
The first TIMESTAMP column in a table is automatically set to the date and time of the most recent operation if you don't assign it a value yourself.
You can also set any TIMESTAMP column to the current date and time by assigning it a NULL value.
DATETIME,字节数为8,取值范围为“1000-01-01 00:00:00——9999-12-31 23:59:59”
对应Java类型为java.sql.Timestamp
INSERT或UPDATE操作时系统不会自动修改其值,不可以设定默认值,为必须字段时必须手动插入,建议使用:new()
MySql按照YYYY-MM-DD HH:MM:SS对数据进行格式化,允许以字符串和数字的方式提交
eg:insert into time_table(CreateDate) values(‘2014-06-09
15:01:01’)
或insert into time_table(CreateDate) values(‘20140609150101’)
TIMESTAMP,字节数为4,取值范围为“19700101080001——20380119111407”
对应Java类型为java.sql.Timestamp
INSERT或UPDATE操作时(且未手动赋值)系统会自动更新、插入当前系统时间,默认值为CURRENT_TIMESTAMP()
提交手动赋值为NULL时也会被赋值为当前系统时间,错误时会填入0
使用TIMESTAMP一定要注意他的时间范围(见上)。

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

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The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA

The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.

The steps to build a MySQL database include: 1. Create a database and table, 2. Insert data, and 3. Conduct queries. First, use the CREATEDATABASE and CREATETABLE statements to create the database and table, then use the INSERTINTO statement to insert the data, and finally use the SELECT statement to query the data.

MySQL is suitable for beginners because it is easy to use and powerful. 1.MySQL is a relational database, and uses SQL for CRUD operations. 2. It is simple to install and requires the root user password to be configured. 3. Use INSERT, UPDATE, DELETE, and SELECT to perform data operations. 4. ORDERBY, WHERE and JOIN can be used for complex queries. 5. Debugging requires checking the syntax and use EXPLAIN to analyze the query. 6. Optimization suggestions include using indexes, choosing the right data type and good programming habits.


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