mysql 存储double数组

CREATE TABLE example (
    id INT PRIMARY KEY,
    double_array TEXT
);

INSERT INTO example (id, double_array) VALUES
(1, '1.1,2.2,3.3');

SELECT id, CAST(SUBSTRING_INDEX(double_array, ',', numbers.n) AS DOUBLE) AS double_value
FROM example
JOIN (
    SELECT 1 n UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5
) numbers
WHERE SUBSTRING_INDEX(SUBSTRING_INDEX(double_array, ',', numbers.n), ',', -1) IS NOT NULL;

CREATE TABLE example (
    id INT PRIMARY KEY,
    double_value1 DOUBLE,
    double_value2 DOUBLE,
    double_value3 DOUBLE
);

INSERT INTO example (id, double_value1, double_value2, double_value3) VALUES
(1, 1.1, 2.2, 3.3);

SELECT id, double_value1, double_value2, double_value3 FROM example;

CREATE TABLE main_table (
    id INT PRIMARY KEY
);

CREATE TABLE double_array_table (
    id INT PRIMARY KEY,
    main_id INT,
    double_value DOUBLE,
    FOREIGN KEY (main_id) REFERENCES main_table(id)
);

INSERT INTO main_table (id) VALUES (1);
INSERT INTO double_array_table (id, main_id, double_value) VALUES
(1, 1, 1.1),
(2, 1, 2.2),
(3, 1, 3.3);

SELECT mt.id, dat.double_value
FROM main_table mt
JOIN double_array_table dat ON mt.id = dat.main_id;