Guruh talabasi Abdig’opporov javoxir Mysql 1-2-amaliy ishlar

ADD FOREIGN KEY (supplierID) REFERENCES suppliers (supplierID);
mysql> DESCRIBE products;
+-------------+------------------+------+-----+------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------+------+-----+------------+----------------+
......
| supplierID | int(10) unsigned | NO | MUL | | |
+-------------+------------------+------+-----+------------+----------------+
mysql> UPDATE products SET supplierID = 502 WHERE productID = 2004;
-- Choose a valid productID
mysql> SELECT * FROM products;
+-----------+-------------+-----------+----------+-------+------------+
| productID | productCode | name | quantity | price | supplierID |
+-----------+-------------+-----------+----------+-------+------------+
| 2001 | PEC | Pencil 3B | 500 | 0.52 | 501 |
| 2002 | PEC | Pencil 4B | 200 | 0.62 | 501 |
| 2003 | PEC | Pencil 5B | 100 | 0.73 | 501 |
| 2004 | PEC | Pencil 6B | 500 | 0.47 | 502 |
+-----------+-------------+-----------+----------+-------+------------+
SELECT with JOIN
SELECT command can be used to query and join data from two related tables. For example, to list the product's name (in products table) and supplier's name (in suppliers table), we could join the two table via the two common supplierID columns:
-- ANSI style: JOIN ... ON ...
mysql> SELECT products.name, price, suppliers.name
FROM products
JOIN suppliers ON products.supplierID = suppliers.supplierID
WHERE price < 0.6;
+-----------+-------+-------------+
| name | price | name |
+-----------+-------+-------------+
| Pencil 3B | 0.52 | ABC Traders |
| Pencil 6B | 0.47 | XYZ Company |
+-----------+-------+-------------+
-- Need to use products.name and suppliers.name to differentiate the two "names"
-- Join via WHERE clause (lagacy and not recommended)
mysql> SELECT products.name, price, suppliers.name