create dida from data6[colname='difference'  COLNAME=
'lower'  COLNAME=
 'Upper'];
	append from data6; 
	close dida;
proc print data=dida; 
run;
I want to have three column names for this dataset, dida, but I only have the first column name right, other two keep as
COL2 COL3.
would anybody teach me how to fix it? Thanks.