topic blank value not counted as null value in SAS Procedures

blank value not counted as null value

nicnad — Thu, 19 Jul 2012 21:05:42 GMT

Hi,

I have a table that contains only alphanumerical values. The column Info1 contains value that are blank (empty).

I usually use the following procedure to count null values in a table, but for this table the result returned is 0, but I see that some values are blank.

proc sql;
select count(Info1) as i from table1

where Info1 is null
;quit;

I also tried this but it also return 0 :

proc sql;
select count(Info1) as i from table1

where Info1=''
;quit;

What am I doing wrong?

Thank you for your help.

Re: blank value not counted as null value

PGStats — Thu, 19 Jul 2012 21:29:11 GMT

COUNT(info1) counts non-missing info1 values. Use COUNT(*) instead. - PG

Re: blank value not counted as null value

Haikuo — Thu, 19 Jul 2012 22:02:01 GMT

PG is dead on this. Count() has tricked me when I first started using Proc SQL. In comparison, sum() is more predictable.

proc sql;
select sum(missing(Info1)) as i from table1

;quit;

Haikuo

Re: blank value not counted as null value

nicnad — Fri, 20 Jul 2012 15:04:10 GMT

Thank you both for this precision.

Regards.