MySQL 的 vsql_currency 扩展

INSTALL EXTENSION vsql_currency;

SELECT EXTENSION_NAME
FROM INFORMATION_SCHEMA.EXTENSIONS
WHERE EXTENSION_NAME = 'vsql_currency';

+----------------+
| EXTENSION_NAME |
+----------------+
| vsql_currency  |
+----------------+

CREATE TABLE prices (
    sku    VARCHAR(8) PRIMARY KEY,
    amount DECIMAL(10,2),
    unit   currency
);

INSERT INTO prices VALUES
    ('A-100', 19.99, 'usd'),
    ('A-101', 24.50, 'EUR'),
    ('A-102', 3100,  'jpy');

SELECT sku, amount, unit FROM prices ORDER BY unit;

+-------+---------+------+
| sku   | amount  | unit |
+-------+---------+------+
| A-101 |   24.50 | EUR  |
| A-102 | 3100.00 | JPY  |
| A-100 |   19.99 | USD  |
+-------+---------+------+

SELECT currency_count() AS codes, is_currency('XYZ') AS xyz, is_currency('GBP') AS gbp;

+-------+------+------+
| codes | xyz  | gbp  |
+-------+------+------+
|   164 |    0 |    1 |
+-------+------+------+

SELECT supported_currencies('C') AS starting_with_c;

+---------------------------------------------------------------------+
| starting_with_c                                                     |
+---------------------------------------------------------------------+
| ["CAD","CDF","CHF","CLP","CNY","COP","CRC","CUC","CUP","CVE","CZK"] |
+---------------------------------------------------------------------+