mysql - 错误代码 : 1241 Operand should contain 1 column(s)

Question

在 mysql 中创建一个函数，当函数被调用时我得到“错误代码:1241 Operand should contain 1 column(s)"如何解决错误

drop function if exists age;

DELIMITER //

CREATE FUNCTION age (Dob date,Username varchar(30))

RETURNS INT

DETERMINISTIC

BEGIN

DECLARE age int;

set age=(SELECT *, YEAR(CURDATE()) - YEAR(Dob)   FROM per_det where username=Username);

return age;

END;//

delimiter ;

select * from per_det;

我收到“错误代码:1241”

Operand should contain 1 column(s)"如何解决错误

Answer 1

您在 SET 子查询中选择了多个列，而 age 期望是单个 INT 值。你不想要这里的 *:

set age=(SELECT YEAR(CURDATE()) - YEAR(Dob)   FROM per_det where username=Username);