When you use SQL summary functions, you need to consider numeric precision and control it by using the ROUND(), FLOOR() and CEIL() functions.

In PROC SQL, there is no concept of order. The results of summary functions can vary with regard to numeric precision when the order, in which the values are encountered by the summary function, changes.

If numeric precision is not controlled, these differences can be especially evident between SAS^® 8 and SAS^®9 software. The reason for the difference is the introduction of threads and threaded procedures in SAS^®9 when the software is running on multiprocessor machines.

If you use summary functions in an SQL query that also takes advantage of multiple threads, the order in which the values are encountered by the summary functions can change from one execution to another.

Operating System and Release Information

Product Family	Product	System	SAS Release
			Reported	Fixed*
SAS System	Base SAS	OpenVMS Alpha	9 TS M0
		Tru64 UNIX	9 TS M0
		64-bit Enabled Solaris	9 TS M0
		HP-UX IPF	9 TS M0
		Linux	9 TS M0
		64-bit Enabled AIX	9 TS M0
		64-bit Enabled HP-UX	9 TS M0
		Microsoft Windows XP Professional	9 TS M0
		Microsoft Windows Server 2003 Standard Edition	9 TS M0
		Microsoft Windows 2000 Professional	9 TS M0
		Microsoft Windows NT Workstation	9 TS M0
		Microsoft Windows Server 2003 Enterprise Edition	9 TS M0
		Microsoft® Windows® for 64-Bit Itanium-based Systems	9 TS M0
		Microsoft Windows 2000 Advanced Server	9 TS M0
		Microsoft Windows Server 2003 Datacenter Edition	9 TS M0
		Microsoft Windows 2000 Server	9 TS M0
		Microsoft Windows Server 2003 Datacenter 64-bit Edition	9 TS M0
		Microsoft Windows Server 2003 Enterprise 64-bit Edition	9 TS M0
		z/OS	9 TS M0
		Microsoft Windows 2000 Datacenter Server	9 TS M0

* For software releases that are not yet generally available, the Fixed Release is the software release in which the problem is planned to be fixed.

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The use of summary or arithmetic functions can highlight differences in numeric precision for resulting values if numeric precision is not taken into account and controlled.

Type:	Usage Note
Priority:

Date Modified:	2008-05-15 14:36:02
Date Created:	2007-11-13 07:36:10