一:mysql基本语句
1.显示可用数据库
show databases;
2.创建一个library数据库
create databaselibrary;
3.使用数据库
use library;
4.查看表
show tables;
5.建表语句
mysql> uselibrary;
Database changed
mysql> createtable viedos(
-> video_id int(11) not nullauto_increment,
-> title varchar(255) not null,
-> director varchar(255) not null,
-> primary key(video_id));
Query OK, 0 rowsaffected (0.30 sec)
6.插入数据
insert intoviedos(video_id,title,director)values
(1,'大上海','武打片'), (2,'小上海','爱情片'),(3,'红上海','喜剧片'),(4,'黑上海','枪打片'),(5,'大上海','散打片');
7.删除表
delete from table_name;
8.更新表数据
update viedos settitle='上海滩' where video_id=1;
二:执行查询语句
A:基本语句
1.查询全部
SELECT * FROMviedos;
2.查询部分
SELECT title FROMviedos;
3.去掉查询结果相同的部分
SELECT distinct title FROM viedos;
SELECT title FROM viedosWHERE director='武打片';
B:使用逻辑比较运算符
创建一张新表:
CREATE TABLE core(
sname VARCHAR(25)NOT NULL,
math INT NOT NULL,
physics INT NOTNULL,
literature INT NOTNULL)
插入数据
INSERT INTO coreVALUES('john',68,37,45),('jim',96,89,92),
('bill',65,12,45),('harry',68,25,82);
查询1:
SELECT * FROM coreWHERE math>90;
查询2:
SELECT sname FROMcore WHERE math>85;
查询3:
SELECT * FROM coreWHERE math
查询4:
SELECTsname,math+physics+literature FROM core;
C:使用函数查询
查询1:
SELECT COUNT(*)FROM core;
查询2:
SELECT AVG(math)FROM core;
查询3:
SELECTMIN(math),MAX(physics) FROM core;
D:筛选查询结果
查询1:降序
SELECT math FROMcore ORDER BY math DESC;
查询2:显示两条记录
SELECT math FROMcore LIMIT 2,2;
查询3:联合使用
SELECT math FROMcore ORDER BY math DESC LIMIT 2,2;
E:使用通配符查询
查询1:
SELECT sname FROMcore WHERE sname LIKE '%j%';
查询2:
SELECT math FROMcore WHERE math LIKE '%6%';

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.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

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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