SAS Certification Prep Guide, 4th Edition

Eliminating Duplicate Rows from Output

In some situations, you might want to display only the unique values or combinations of values in the column(s) listed in the SELECT clause. You can eliminate duplicate rows from your query results by using the keyword DISTINCT in the SELECT clause. The DISTINCT keyword applies to all columns, and only those columns, that are listed in the SELECT clause. We see how this works in the following example.

Example

Suppose you want to display a list of the unique flight numbers and destinations of all international flights that are flown during the month.

The following SELECT statement in PROC SQL selects the columns FlightNumber and Destination in the table Sasuser.Internationalflights:

proc sql outobs=12; ...