MySQL 的 vsql_complex 扩展

INSTALL EXTENSION vsql_complex;

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

+----------------+
| EXTENSION_NAME |
+----------------+
| vsql_complex   |
+----------------+

CREATE TABLE signals (
    id        INT PRIMARY KEY,
    impedance COMPLEX
);

INSERT INTO signals VALUES
    (1, '(50.0,0.0)'),
    (2, '(3.0,4.0)'),
    (3, '(0.0,-2.5)');

SELECT id, impedance,
       complex_real(impedance) AS re,
       complex_imag(impedance) AS im,
       complex_abs(impedance) AS magnitude
FROM signals;

+----+-----------+------+------+-----------+
| id | impedance | re   | im   | magnitude |
+----+-----------+------+------+-----------+
|  1 | (50,0)    |   50 |    0 |        50 |
|  2 | (3,4)     |    3 |    4 |         5 |
|  3 | (0,-2.5)  |    0 | -2.5 |       2.5 |
+----+-----------+------+------+-----------+

SELECT complex_multiply(impedance, '(0,1)') AS rotated FROM signals WHERE id = 2;
SELECT complex_sum(impedance) AS total FROM signals;

+---------+
| rotated |
+---------+
| (-4,3)  |
+---------+
+----------+
| total    |
+----------+
| (53,1.5) |
+----------+