SAS 9.4 SQL Procedure User's Guide, Fourth Edition, 4th Edition

• In general, indexing on a column with a small number (less than 6 or 7) of distinct

values does not result in a performance gain.

• You can use the same column in a simple index and in a composite index. However,

for tables that have a primary key integrity constraint, do not create more than one

index that is based on the same column as the primary key.

Deleting Indexes

To delete an index from a table, use the DROP INDEX statement. The following DROP

INDEX statement deletes the index Places from NewCountries:

proc sql;

drop index places from sql.newcountries;

Deleting a Table

To delete a PROC SQL table, use the DROP TABLE statement:

proc sql;

drop table sql.newcountries;

Using SQL Procedure Tables in SAS Software

Because PROC SQL tables are SAS data files, you can use them as input to a DATA step

or to other SAS procedures. For example, the following PROC MEANS step calculates

the mean for Area for all countries that are in the Countries table:

proc means data=sql.countries mean maxdec=2;

title "Mean Area for All Countries";

var area;

run;

Output 4.12 Using a PROC SQL Table in PROC MEANS

128 Chapter 4 • Creating and Updating Tables and Views