The ALTER TABLE Statement

The ALTER TABLE statement is used to add, delete, or modify columns in an existing table.
Syntax: 
To add-  ALTER TABLE <table_name> ADD <column_name>  datatype
To delete a col-  ALTER TABLE table_name DROP COLUMN column_name
To chng datatyp of col-  ALTER TABLE table_name ALTER COLUMN column_name datatype

The CREATE TABLE Statement

The CREATE TABLE statement is used to create a table in a database.
Syntax:
CREATE TABLE <table_name>
(
<column_name1> <data_type>,
<column_name2> <data_type>,
<column_name3> <data_type>,
....
)
Example:
 Now we want to create a table called "Persons" that contains five columns: P_Id, LastName, FirstName, Address, and City.
Query:
CREATE TABLE Persons
(
P_Id int,
LastName varchar(255),
FirstName varchar(255),
Address varchar(255),
City varchar(255)
)
Output:
The empty "Persons" table will now look like this:

P_Id    LastName    FirstName    Address    City      
                   

The CREATE DATABASE Statement

The CREATE DATABASE statement is used to create a database.
Syntax:           CREATE DATABASE <database_name>
Example:         CREATE DATABASE my_db