用SAS程序写出现有数据集a变量x为受试者编号y为基线滴度数据z为基线阳性阴性；数据集b变量x为受试者编号变量m为基线后的滴度数据。请找出受试者所有的观测满足基线阳性但全部基线后滴度基线ADA阳性样本的4倍这样的受试者才符合条件请写出程序

data a; input x y z; datalines; 1 10 1 2 20 0 3 5 1 4 15 1 5 8 0 ; run;

data b; input x m; datalines; 1 30 2 40 3 3 4 60 5 20 ; run;

proc sql; create table c as select a.x, a.y, a.z, b.m from a inner join b on a.x = b.x where a.z = 1 and b.m < a.y * 4; quit;