This example shows how you can use USING(xxxx) to supply an OMIT statement to remove certain input records and an INREC statement to reformat certain input records before SELECT processing begins.

 SELECT FROM(INB) TO(OUTB) ON(8,10,CH) -
   FIRSTDUP USING(BIRD)

Let's say the INB data set looks like this:

TYPE1  CROWS
TYPE1  PIGEONS
TYPE1  HAWKS
TYPE1  ROBINS
TYPE1  SPARROWS
TYPE1  CHICKENS
TYPE1  RAVENS
TYPE2            PIGEONS
TYPE2            ROBINS
TYPE2            HAWKS
TYPE2            TERNS
TYPE3  EAGLES
TYPE3  STARLINGS

We want to remove the TYPE3 records and then select one record for each type of bird that appears in both a TYPE1 and a TYPE2 record. We could use the following control statements in BIRDCNTL:

* Remove the TYPE3 records.
  OMIT COND=(1,5,CH,EQ,C'TYPE3')
* Reformat the TYPE2 records to place the bird name in
* same place as in the TYPE1 records so we can match them.
  INREC IFTHEN=(WHEN=(1,5,CH,EQ,C'TYPE2'),
         BUILD=(8:18,10))

The OUTB data set would look like this:

TYPE1  HAWKS
TYPE1  PIGEONS
TYPE1  ROBINS