如何获得此子查询的结果

Question

我有两张桌子

CREATE TABLE `A_Lab_Project` (
        `subject_code` varchar(8) NOT NULL,
        `semester` int(11) NOT NULL DEFAULT '0',
        `branch_code` varchar(3) NOT NULL DEFAULT '',
        `component` varchar(50) DEFAULT NULL,
        `course_outcome` int(11) DEFAULT NULL,
        `max_marks` int(11) DEFAULT NULL,
        `syear` varchar(6) DEFAULT NULL,
        `eyear` varchar(20) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1; 

 CREATE TABLE `A_Lab_Program` (
    `subject_code` varchar(8) NOT NULL,
    `semester` int(11) NOT NULL DEFAULT '0',
    `branch_code` varchar(3) NOT NULL DEFAULT '',
    `Question_no` varchar(50) DEFAULT NULL,
    `Marks_co1` int(11) DEFAULT NULL,
    `Marks_co2` int(11) DEFAULT NULL,
    `Marks_co3` int(11) DEFAULT NULL,
    `Marks_co4` int(11) DEFAULT NULL,
    `syear` varchar(6) DEFAULT NULL,
    `eyear` varchar(20) DEFAULT NULL ) 

我需要

100*(v1+v2)/v3+v4 ; 
v1 = select sum(course_outcome) from A_Lab_Project where subject_code='12csa34',
v2 = select sum(max_co) from A_Lab_Program where subject_code='12csa34', 
v3 = select max_marks from A_Lab_Project where subject_code='12csa34' 

在子查询中请帮我写一个子查询。