mysql自定义函数求方程

MySQL可以通过自定义函数来求解方程，以下是一个示例，可以求解一元二次方程ax^2+bx+c=0的解：

CREATE FUNCTION solve_quadratic_equation(a DOUBLE, b DOUBLE, c DOUBLE)
RETURNS VARCHAR(100)
BEGIN
    DECLARE discr DOUBLE;
    DECLARE x1 DOUBLE;
    DECLARE x2 DOUBLE;
    DECLARE result VARCHAR(100);
    
    SET discr = b*b - 4*a*c;
    
    IF discr < 0 THEN
        SET result = 'This equation has no real roots.';
    ELSEIF discr = 0 THEN
        SET x1 = -b / (2*a);
        SET result = CONCAT('This equation has one root: ', x1);
    ELSE
        SET x1 = (-b + SQRT(discr)) / (2*a);
        SET x2 = (-b - SQRT(discr)) / (2*a);
        SET result = CONCAT('This equation has two roots: ', x1, ' and ', x2);
    END IF;
    
    RETURN result;
END;

然后我们可以调用这个函数来求解方程，例如：

SELECT solve_quadratic_equation(2, -7, 3);

这会返回 "This equation has two roots: 3 and 0.5"。