%let vars=Con_EnergyConsumption Con_Modeling Con_Noise Con_Operation Con_Strength Con_Water_con Con_dehydration Con_washeffect;
Proc sql;
select distinct count(scan("&vars.",," ")) into : count_vars
from sashelp.class(obs=1);
quit;
我通过数据字典得到了我想要的变量并赋予vars,我想自动判断vars中有多少个变量。怎么做，我这样是错的。