MySQL Database common statements

About the collation of common commands in MySQL database:

One: For the operation of the database

show databases; Displays all database names under the current user

Use database_name; Enter the current database

CREATE DATABASE database_name;

DROP DATABASE database_name;

Second: The operation of the table

DDL operations: Data Definition language

CREATE TABLE table_name (

ID int primary KEY auto_increment,

Name varchar (20),

); Build a Table statement

DROP TABLE TABLE_NAME, delete the statement of the tables, delete the contents of the table and the table structure directly.

TRUNCATE TABLE table_name; Deletes the contents of the tables, preserves the structure of the table, and does not roll back, the efficiency is high.

Delete from Talbe_name, deleting the contents of the table, without deleting the table's mechanism, is less efficient than truncate.

Rename table Old_name to new_name; Modify the name of the tables.

ALTER TABLE table_name ADD COLUMN_NAME varchar (30);

ALTER TABLE table_name DROP COLUMN_NAME varchar (30);

ALTER TABLE table_name MODIFY COLUNM_NAME varchar (30);

DESC table_name; Query table structure

DML: Data Manipulation language

Delete from table_name where column_table=column_value; Delete data under condition

UPDATE table_name Set column_name= ", column=" where column_name=column_value; updates the data under the condition

INSERT INTO table_name (column_name1,column_name2 ...) VALUES (Column_values,column_values,...);

Query statement:

SELECT * FROM table_name where column_name=column_value; query the data that satisfies the condition based on the specific conditions

Select A.column1,a.column2,... from table_name where column_name=column_value; query data for some fields based on criteria

There are also sub-queries, sequences, views, and indexes.

MySQL Database common statements