-- Create a table

CREATE TABLE xyz
(
	age INT,
	name VARCHAR(100)
);

-- Not NULL means you cannot have unknown values

CREATE TABLE xyz
(
	age INT NOT NULL,
	name VARCHAR(100) NOT NULL
);

-- Setting Default Values for NOT NULL types

CREATE TABLE xyz
(
	age INT DEFAULT 20,
	name VARCHAR(100) DEFAULT 'abc'
);

-- Setting a Primary Key for the Table

CREATE TABLE xyz
(
	id INT NOT NULL,
	age INT DEFAULT 20,
	name VARCHAR(100) DEFAULT 'abc',
	PRIMARY KEY (id)
);

-- Numbers IDs serially

CREATE TABLE xyz
(
	id INT NOT NULL AUTO_INCREMENT,         -- Dont specify ID at all
	age INT DEFAULT 20,
	name VARCHAR(100) DEFAULT 'abc',
	PRIMARY KEY (id)
);

-- Alter Table Size Allocation after Creation
ALTER TABLE shirts MODIFY COLUMN shirt_size VARCHAR(2);