Logic difference between INOBS= and OBS=?

[cosmid]

Hi,

From the definition of the two:

INOBS= is restricting the number of input rows

OBS= is specifying the last observation

Based on that, I couldn't think of a scenario where the two are different. Are they logically the same thing?

Thanks

[yabwon · Accepted solution]

1) INOBS= is Proc SQL spacific,

2) OBS= is global option and data set option

3) INOBS= produces a warning

4) OBS= can overwrite INOBS=

See this:

1    proc sql INOBS=10;
2      select * from sashelp.class;
WARNING: Only 10 records were read from SASHELP.CLASS due to INOBS= option.
3    quit;
NOTE: PROCEDURE SQL used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds


4
5
6    proc sql INOBS=10;
7      select * from sashelp.class(obs=5);
8    quit;
NOTE: PROCEDURE SQL used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds


9
10   proc sql;
11     select * from sashelp.class(obs=5);
12   quit;
NOTE: PROCEDURE SQL used (Total process time):
      real time           0.00 seconds
      cpu time            0.01 seconds


13
14   data test1;
15     set sashelp.class(obs=5);
16   run;

NOTE: There were 5 observations read from the data set SASHELP.CLASS.
NOTE: The data set WORK.TEST1 has 5 observations and 5 variables.
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds


17
18   data test2;
19     set sashelp.class(inobs=5);
                         -----
                         22
ERROR 22-7: Invalid option name INOBS.

20   run;

NOTE: The SAS System stopped processing this step because of errors.
WARNING: The data set WORK.TEST2 may be incomplete.  When this step was stopped there were 0
         observations and 0 variables.
WARNING: Data set WORK.TEST2 was not replaced because this step was stopped.
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds

Bart

[SASJedi]

inObs= specifies the total number of rows to read in. obs= specifies the row number where you should stop reading. The firstObs= option specifies the first row of data tobe read, and it's easier to see the difference between obs= and inObs= if you apply firstOBS= in conjunction with those options and compare the results: 

/* inObs= vs obs= with firstObs=*/
proc sql inobs=50 number;
title 'InObs=50, firstObs=20';
select *
	from sashelp.cars(firstObs=20)
;
quit;

title 'obs=50, firstObs=20';
proc sql number;
title 'obs=50, firstObs=20';
select *
	from sashelp.cars(firstObs=20 obs=50)
;
quit;

Note that the first query returns 50 rows, but the second query only returns 31 rows.