data _null_;
    set sashelp.vcolumn end=last;
        where libname="WORK" and memname="AAA" and index(label,"(");
        do until(index(label,"(")=0);
           if label =:"(" then label=substr(label,index(label,")")+1);
       else label=substr(label,1, index(label,"(")-1)|| substr(label,index(label,")")+1);
        end;

        length setlabel $100;
        setlabel=catx(" ",setlabel, catx("=",name,quote(strip(label))));
        retain setlabel;
        if last then call symputx("setlabel",setlabel);
run;

proc datasets lib=work;
   modify aaa;
   label &setlabel;
run;quit;

:"("  表示什么意思？谢谢！
如果括号就有中文状态的括号和英文状态的括号呢？

=: 相当于sql中用的 eqt。

In a truncated string comparison, the comparison is performed after making the strings the same length by truncating the longer string to be the same length as the shorter string. For example, the expression 'TWOSTORY' eqt 'TWO' is true because the string 'TWOSTORY' is reduced to 'TWO' before the comparison is performed.

学习了