SAS Certification Prep Guide, 4th Edition

Controlling Execution

Restricting Row Processing

When you are developing queries against large tables, you can reduce the amount of time that it takes for the queries to run by reducing the number of rows that PROC SQL processes. Subsetting the tables with WHERE clauses is one way to do this. Using the INOBS= and OUTOBS= options in PROC SQL is another way.

You already know that you can use the OUTOBS= option to restrict the number of rows that PROC SQL displays or writes to a table. However, the OUTOBS= option does not restrict the rows that are read. The INOBS= option restricts the number of rows that PROC SQL takes as input from any single source. The INOBS= option is similar to the SAS system option OBS= and is useful for debugging queries ...