评估PROC SQL中的字符和数字变量

Question

我正在尝试评估PROC SQL中的变量是字符还是数字。然后，这将确定要使用哪个WHERE子句。我以为使用VTYPE会给我想要的结果，但听起来你不能在PROC SQL中使用该功能。是否有一个特定的函数可以在PROC SQL中使用，它将返回变量类型并在if语句中进行求值？如何将该函数合并到SQL代码中？

我的完整代码如下：

%MACRO miss_count(vars=,dataset=,business_line=);
PROC SQL;
SELECT s1.&vars, s1.year AS years, 
COUNT(*) AS missing, 
(SELECT COUNT(*) FROM saslib.&dataset AS s2 WHERE s2.year=s1.year) AS total, 
(COUNT(*)/(SELECT COUNT(*) FROM saslib.&dataset AS s3 WHERE s3.year=s1.year))*100 AS perc_missing
FROM saslib.&dataset AS s1
%IF VTYPE(&vars) = 'C' %THEN WHERE s1.&vars IN (' ', 'UNKN', 'NONE') %ELSE WHERE s1.&vars IN (.)
AND s1.bus_line = &business_line
GROUP BY s1.&vars, s1.year;
QUIT;
%MEND miss_count;

%miss_count(vars=cpt_typcode, dataset=sample, business_line='COM')

然而，当我运行此代码时，我收到错误：

ERROR: Required operator not found in expression: VTYPE(&vars) = 'C' 
ERROR: The macro MISS_COUNT will stop executing.

我是SAS的新手，我想知道如何在PROC SQL中评估变量是字符还是数字。

有关详细信息，请参见下面的输出。

MLOGIC(MISS_COUNT):  Beginning execution.
MLOGIC(MISS_COUNT):  Parameter VARS has value cpt_typcode
MLOGIC(MISS_COUNT):  Parameter DATASET has value sample
MLOGIC(MISS_COUNT):  Parameter BUSINESS_LINE has value 'COM'
MPRINT(MISS_COUNT):   PROC SQL;
ERROR: Required operator not found in expression: VTYPE(&vars) = 'C' 
ERROR: The macro MISS_COUNT will stop executing.
MPRINT(MISS_COUNT):   SELECT s1.cpt_typcode, s1.year AS years, COUNT(*) AS missing, (SELECT COUNT(*) FROM saslib.sample AS s2 WHERE 
s2.year=s1.year) AS total, (COUNT(*)/(SELECT COUNT(*) FROM saslib.sample AS s3 WHERE s3.year=s1.year))*100 AS perc_missing FROM 
saslib.sample AS s1
MLOGIC(MISS_COUNT):  Ending execution.