how to makea a small database in sql code example

Example: CREATE DATABASE DatabaseName;

SHOW DATABASES;
 DROP DATABASE testDB;
 USE DatabaseName;
 
 SQL> CREATE TABLE CUSTOMERS(
   ID   INT              NOT NULL,
   NAME VARCHAR (20)     NOT NULL,
   AGE  INT              NOT NULL,
   ADDRESS  CHAR (25) ,
   SALARY   DECIMAL (18, 2),       
   PRIMARY KEY (ID)
);

DESC CUSTOMERS;