I:
Operating system: Win11 system
mysql version: 8.0.34
Note: When the MySQL database is started, the default port number occupied is 3306
cmd commands are not case sensitive
cmd window (administrator) to start and shut down MySQL:
Start: net start MySQL80
shutdown: net stop mysql80
dos command window: mysql -uroot -p password (display password) mysql -uroot -p (hide password)
Exit mysql: exit
View the databases in the mysql database: show databases; (remember to bring English semicolons)
Use a database: use + database name; (remember to add a semicolon)
Create a database command: create database name;
1. MySQL------table
View those tables under the database: show tables;
Data is represented in the form of tables in the database (more intuitive).
Any table has rows and columns
Row: called record/data
Columns: called fields
Field: field name, data type, constraints and other attributes!
Unique constraint (unique): The data in this field cannot be repeated.
Two, the classification of SQL statements
DQL: Data Query Language (everything with the select keyword is a query statement)
select .......
View the data in the table: select * from table name
Look at the structure of the table, not the data in the table: desc table name
DML: data manipulation language (anything that adds, deletes, or modifies data in a table is DML), mainly operates the data in the table
insert: increase
delete: delete
update: change
DDL: Data definition language (everything with create, drop, alter, is DDL). DDL mainly operates on the structure in the table, not the data in the table.
create: Create a new one, which is equivalent to adding
drop: delete
alter: modify
This should be distinguished from DML, which modifies not the data in the table, but the structure of the table.
TCL: Transaction Control Language
commit: transaction commit
rollback: transaction rollback
DCL: Data Control Language
grant: authorization
revoke: revoke permission
Three, MySQL commonly used commands
Notice:
MySQL does not execute if there is no semicolon, and the semicolon means the end. So every command should end with a semicolon! ! !
When we make a mistake in a command, use \c to end this wrong command!
SQL statements are case insensitive!
1. View the version number of the MySQL database: select version()
2. Check which database is currently in use: select database(), note: this bjpowernode database is created by myself just now, not in mysql! ! !
3. Check the databases in the mysql database: show databases (the bjpowernode database is created by yourself, and the others are mysql databases)
4. Use a database: use + database name
5. Create a database command: create database file name
6. Check the tables under the database: show tables
7. View the data in the table: select * from table name
8. Look at the structure of the table, not the data in the table: desc table name
9. Exit mysql: exit
10. Import data: source data path
11. Delete the database: drop database database name
12. View the statement to create a table: show create table table name