这个MySQL触发器让我这个错误子查询返回超过1行

Question

DELIMITER $$
CREATE TRIGGER Product_Trigger
    AFTER UPDATE ON PRODUCT
    FOR EACH ROW
BEGIN
    INSERT INTO AUDITTRAIL
    SET activity = 'updated Product',
     employeeName = (select (select concat(firstName,' ',LastName) from employee) from userAccount where accountstatus = 1),
        employeeID = (select employeeID from userAccount where accountStatus=1),
        activityDate = NOW();
END$$
DELIMITER ;