MySQL: DEFAULT constraint is easy

#MySQL #course #tutorial

00:00:00 intro
00:02:25 DEFAULT when creating a table
00:03:26 DEFAULT for an existing table
00:05:19 example 2
00:07:56 conclusion

– EXAMPLE 1
CREATE TABLE products (
product_id INT,
product_name varchar(25),
price DECIMAL(4, 2) DEFAULT 0
);

ALTER TABLE products
ALTER price SET DEFAULT 0;

INSERT INTO products (product_id, product_name)
VALUES (104, "straw"),
(105, "napkin"),
(106, "fork"),
(107, "spoon");
SELECT * FROM products;

– EXAMPLE 2
CREATE TABLE transactions(
transaction_id INT,
amount DECIMAL(5, 2),
transaction_date DATETIME DEFAULT NOW()
);
SELECT * FROM transactions;

INSERT INTO transactions (transaction_id, amount)
VALUES (1, 4.99);
SELECT * FROM transactions;

INSERT INTO transactions (transaction_id, amount)
VALUES (2, 2.89);
SELECT * FROM transactions;

INSERT INTO transactions (transaction_id, amount)
VALUES (3, 8.37);
SELECT * FROM transactions;

DROP TABLE transactions;