改进 %NRQUOTE 'removal'

Question

我有以下有效的代码，但我想知道是否有人可以提出 'removing' 和 %nrquote 的更好方法。我不得不添加一个 %SUBSTR 函数，该函数有效，但我很想知道是否还有其他建议，以及是否有人可以帮助解释为什么没有 %let 代码无法工作mvar 宏定义中的语句。

/* Automatically generated by DI Studio - cannot change */
%let _where_clause = %nrquote(name = %'Henry%');
%let _mac1 = %nrquote(lemk);
%let _variable = weight;
%let _input0 = sashelp.class;
/* End of auto-generated code */

options mprint;

%macro mvar;
    %if &_where_clause ^= %then %do;
        /* Re-assign the _where_clause variable to 'remove' %nrquote */
        %let _where_clause = %substr(&_where_clause,1);
        where &_where_clause
    %end;
%mend mvar;

proc sql;
    select &_variable into :&_mac1
    from &_input0
    %mvar
    ;
quit;

如果没有 %let 语句，代码将失败并出现此错误：

NOTE: Line generated by the macro variable "_WHERE_CLAUSE".
1     name = 'Henry'
             -
             22
MPRINT(MVAR):   where name = '
NOTE: Line generated by the macro variable "_WHERE_CLAUSE".
1     name = 'Henry'
             -
             200
ERROR 22-322: Syntax error, expecting one of the following: a name, a quoted string,
              a numeric constant, a datetime constant, a missing value, (, *, +, -, ALL, ANY,
              BTRIM, CALCULATED, CASE, INPUT, PUT, SELECT, SOME, SUBSTRING, TRANSLATE, USER.

ERROR 200-322: The symbol is not recognized and will be ignored.

114          ;
MPRINT(MVAR):  Henry'

Answer 1

您需要 %UNQUOTE，这是 %LET 正在发生的事情，它取消引用引号。

Change 
where &_where_clause
to 
where %unquote(&_where_clause)

改进 %NRQUOTE 'removal'

Improvement on %NRQUOTE 'removal'

sas

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