mysql 矩阵乘法函数

DELIMITER //

CREATE FUNCTION MatrixMultiply(A TEXT, B TEXT)
RETURNS TEXT
DETERMINISTIC
BEGIN
    DECLARE rowsA INT;
    DECLARE colsA INT;
    DECLARE rowsB INT;
    DECLARE colsB INT;
    DECLARE result TEXT;
    DECLARE i INT;
    DECLARE j INT;
    DECLARE k INT;
    DECLARE sum FLOAT;

    SET rowsA = LENGTH(A) / (SELECT LENGTH(SUBSTRING_INDEX(A, ',', 1)) - 1);
    SET colsA = SELECT LENGTH(SUBSTRING_INDEX(A, ',', 1)) - 1;
    SET rowsB = LENGTH(B) / (SELECT LENGTH(SUBSTRING_INDEX(B, ',', 1)) - 1);
    SET colsB = SELECT LENGTH(SUBSTRING_INDEX(B, ',', 1)) - 1;

    IF colsA <> rowsB THEN
        SIGNAL SQLSTATE '45000'
        SET MESSAGE_TEXT = 'Matrix dimensions do not match for multiplication';
    END IF;

    SET result = '';

    FOR i = 0 TO rowsA - 1 DO
        FOR j = 0 TO colsB - 1 DO
            SET sum = 0;
            FOR k = 0 TO colsA - 1 DO
                SET sum = sum + SUBSTRING_INDEX(SUBSTRING_INDEX(A, ',', i * colsA + k + 1), ',', -1) * SUBSTRING_INDEX(SUBSTRING_INDEX(B, ',', k * colsB + j + 1), ',', -1);
            END FOR;
            IF j < colsB - 1 THEN
                SET result = CONCAT(result, SUM, ',');
            ELSE
                SET result = CONCAT(result, SUM);
            END IF;
        END FOR;
        IF i < rowsA - 1 THEN
            SET result = CONCAT(result, ';');
        END IF;
    END FOR;

    RETURN result;
END //

DELIMITER ;

SET @matrixA = '1,2,3;4,5,6';
SET @matrixB = '7,8;9,10;11,12';
SELECT MatrixMultiply(@matrixA, @matrixB);

58,64;139,154