FIX: Error: "Cannot Nest Aggregate Functions"

ID: Q154023

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b
Microsoft FoxPro for Windows, versions 2.6, 2.6a
Microsoft FoxPro for MS-DOS, versions 2.6, 2.6a

SYMPTOMS

The following error occurs when running a form containing Structured Query Language (SQL) code:

"Error Loading File - Loading Form or the Data Environment - Record number 44. Cannot Nest Aggregate Functions".

The record number that the error is referring to is always the FORM itself. In other words, the CLASS field contains 'FORM' and OBJECTNAME = 'FORM1'.

CAUSE

The cause of this problem is related to the way FoxPro internally parses the SQL code. The code is parsed and assigned an internal number. The number assigned is entirely dependent on the code itself and the order it is being generated in. In this case, the number generated is similar to the token for the SQL aggregate count; thus, FoxPro thinks that it has been nested.

WORKAROUND

The workaround is to change the order of the code. This can be accomplished in several different ways, depending on the code itself. For example, if User Defined Functions (UDFs)are being used by the code, they could be moved to another procedure. If IIF statements are being used, those could be moved to a .PRG file and then called as UDFs. Both of these will change the order in which the code is being parsed and will result in a different generated number. Since there are only a few numbers out of millions that may conflict, the chances of ever seeing the error again are very slim.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. This problem has been fixed in Visual FoxPro 5.0 for Windows.

Additional query words:

Keywords : kbVFp kbVFP260bug FoxDos FoxWin FxprgSql kbvfp260abug
Version : MS-DOS:2.6,2.6a; WINDOWS:2.6,2.6a,3.0,3.0b
Platform : MS-DOS WINDOWS
Issue type :