Introduction to MySQL SQL and basic commands

SQL composition

SQL full name is Structured Query language, according to the function, the SQL language mainly consists of the following parts.

• dml--data manipulation language used to insert, modify, and delete data in a database.
• ddl--The data definition language, establishes the database, database objects, and defines its columns.
• dql--data Query Language, query the data in the database
• dcl--Data Control Language, control database component access permission, access permissions, etc. such as Grant, REVOKE.

Common commands in MySQL

MySQL query is case insensitive by default

DOS Boot service:

net start MySQL start MySQL service

net stop MySQL stop MySQL service

Command line Login:

Mysql–u Root–p (you will be prompted to enter the password)

PS: If you are connecting to another machine, you need to add a parameter:-H machine IP

Basic operation:

Status Displays the current running status of the MySQL service

Select version (); Show current MySQL version

Select Current_date; Show current date (case-sensitive)

Select Now (); Displays the current date, time

Select Database (); Displays the database currently in use

Library operation (Action statement to; end):

show databases; Show all databases

Create DATABASE <database name>; Create a database

Drop database <database name> directly deletes the databases without alerting

MySQL admin drop <database name> before deleting the database, there are hints

Use <database name>; Open Database

Show tables; Show all tables in the database

Table Operation:

CREATE TABLE <table name>

(Field 1 data type, field 2 data type); Build table

drop table <table name>; Delete a table

Describe <table name>; Structure of the Display table

Desc <table name>; Structure of the Display table

SELECT * FROM <table name> display the contents of the table

Delete from <table name>; Clear the contents of the table

Introduction to MySQL SQL and basic commands