给你sas的解释你可以看一下。
Example 1: Quoting a Value that Might Contain a Mnemonic Operator
The macro DEPT1 receives abbreviations for states and therefore might receive the value OR for Oregon.
%macro dept1(state);
      /* without %quote -- problems might occur */
   %if &state=nc %then
       %put North Carolina Department of Revenue;
   %else %put Department of Revenue;
%mend dept1;

%dept1(or)
When the macro DEPT1 executes, the %IF condition executes a %EVAL function, which evaluates or as a logical operator in this expression. Then the macro processor produces an error message for an invalid operand in the expression or=nc .
The macro DEPT2 uses the %QUOTE function to treat characters that result from resolving &STATE as text:
%macro dept2(state);
      /* with %quote function--problems are prevented */
   %if %quote(&state)=nc %then
       %put North Carolina Department of Revenue;
   %else %put Department of Revenue;
%mend dept2;

%dept2(or)
The %IF condition now compares the strings or and nc and writes to the SAS log:
Department of Revenue

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