topic Re: Proc sql in SAS Procedures

Proc sql

shivamarrora0 — Sun, 30 Jul 2017 18:29:07 GMT

Hi All, can you please explain crisply how the below query is working,

i wanted to know how where confition checking the each observtion of table b with every observation of table a.

/* Quesry is used to find the ranks*/

data a;
input id sal;
cards;
1 100
2 200
3 300
9 78
10 890
11 890
;

proc sql;
select a.*,(select count(distinct sal) from a where b.sal le a.sal) as r from a b;
quit;

Re: Proc sql

ChrisBrooks — Sun, 30 Jul 2017 23:35:52 GMT

Quite simply a and b are the same table which you are joining with itself - b is just an alias for a which is set up by the "from a b" portion of the query.

Re: Proc sql

PGStats — Mon, 31 Jul 2017 01:38:04 GMT

Conceptually, SAS is running a subquery for every observation of table a. Since that subquery also involves table a, you must give the table an alias name (b) so as to allow an expression like "b.sal le a.sal". I think the query should be written as

proc sql;
select 
	b.*,
	(	select 
			count(distinct id) 
		from a 
		where b.sal le a.sal	) as r 
from a as b;
quit;

Re: Proc sql

shivamarrora0 — Mon, 31 Jul 2017 04:59:32 GMT

Hi, I wanted to know the reason why b.sal le a.sal
comparing 1 observation of B table to every observation of A table .. ?

Re: Proc sql

LinusH — Mon, 31 Jul 2017 06:25:09 GMT

Well, it's your program and your data, so basically you should know better than us what this program's task is.

Re: Proc sql

ballardw — Mon, 31 Jul 2017 14:48:43 GMT

@shivamarrora0 wrote:
Hi, I wanted to know the reason why b.sal le a.sal
comparing 1 observation of B table to every observation of A table .. ?

This would one approach to "how many salary values are the same or more than the person with the givend ID, including that person".

Is a "what" answer. Why is up to your rules.