MySQL - 1, database and table operations

CREATE DATABASE

Create a database called "example_db":

CREATE DATABASE example_db;

CREATE TABLE

Create a table called "employees" to store employee information:

CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(50),
    age INT,
    department VARCHAR(50)
);

ALTER TABLE

Add a new column "salary" to the "employees" table:

ALTER TABLE employees
ADD COLUMN salary DECIMAL(10, 2);

DROP DATABASE

Drop the database named "example_db" and all tables in it:

DROP DATABASE example_db;

DROP TABLE

Drop the table named "employees":

DROP TABLE employees;

TRUNCATE TABLE

Clear all data in the "employees" table, but keep the structure of the table:

TRUNCATE TABLE employees;

RENAME TABLE

Rename the "employees" table to "staff":

RENAME TABLE employees TO staff;

In practical applications, operations on databases and tables need to be done carefully to ensure that you understand the consequences of operations to avoid irreversible data loss. It is strongly recommended to make a backup before deleting!