DB mysql Basic Query - CREATE(DB, Table), Add(Column), Delete(DB, Table, Column)

OS : Ubuntu

Start mysql

- sudo mysql

Shows the current DB

- SHOW DATABASES;

Create DataBase

-> CREATE DATABASE [DB name];

Delete DB

-> DROP DATABASE [DB name];

Warning: If you delete the DB, the data will also be deleted.

Use the DB

-> USE [DB name];

Create Table

-> CREATE TABLE [Table name](

    [column name] INT NOT NULL AUTO_INCREMENT, -> id is primary number

    [column name] VARCHAR(255) NOT NULL,

    PRIMARY KEY([column name])

    );

INT : integer number

NOT NULL : Not allow null

AUTO_INCREMENT : id number will increase automatically

VARCHAR : You could type string

PRIMARY KEY([column name]) : Assign a Primary key

Show tables

-> SHOW TABLES;

Add column in the existed table

-> ALTER TABLE [table name]

    ADD COLUMN [column name] INT AFTER [existed column name]; -> 'age' is what you want to add

ALTER TABLE [table name] : Update table

ADD COLUMN : Add column

AFTER name : column 'name' is already existed. So 'age' column will add next to the 'name'.

Show columns

-> SHOW COLUMNS FROM [Table name];

Delete Table Column

-> ALTER TABLE [table name]

    DROP COLUMN [column you want to delete];

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