data a;
input x $19.;
cards;
a"+"aaaaa
c'+'cccc
haha"+"hahaha
;
run;

%macro sh(note);
data b;
y="&note";
run;
%mend;

data _null_;
set a;
call execute('%nrstr(%sh('||'%bquote('||strip(x)||")))");
run;

data a;
input x $19.;
cards;
A"+"B
;
run;

%macro sh(note);
data b;
y="&note";              /* the y hold character string */
put "y= " y;
run;
%mend;

%sh(%nrbquote(A"+"B));  
                                          /* OK ,    output: y = A"+"B  */
%sh( A);                   /*  OK,   output:  y = A  */
%sh(A"+"B);             /* error, Character values have been converted to numeric values */
                    /* reason:  the left " in %sh() was combine with the first " in %sh(A"+"B) and
                                     the right " in %sh() was combined with the second " in %sh(A"+"B) to produce
                                    "A"+"B" this caused the error since y want a character string   */         
%sh(A+B);           /*   OK,    output: y = A+B */
%sh(A+"B");        /* error:    Character values have been converted to numeric values */

data _null_;
set a;
* call execute(  '%sh(A"+"B)' );                        /* error: data b; y="A"+"B"; */
* call execute(  '%sh(%nrbquote(A"+"B))');     /* data b; y="A" + "B"; */
call execute(  '%sh(A+B)'  );                              /* OK  output: y=A+B */
run;              /* NOTE use single quotation around the macro %sh(A+B) */

From the log message, it seems that the quotation mark inside macro (ie.  Y=”&note”) were mixed up with the quotation mark in the CALL EXECUTE statement.
This is because the macro variable in CALL EXECUTE statement was resolved immediately.

个人认为这个问题的关键有两个地方：
1. 要使call execute中对宏的引用在数据步执行过程中执行；
2. 要使%bquote也作为宏引用中的一部分。也就是说%bquote要加引号使其作为字符串。

这太深了，不懂。学习下

看来我对宏的理解是白学了。