Extending Functions In SQL 7.0?

Is there a way to add functions to SQL (other than stored proceedures) to emulate functions in other systems?

I would like to create a FOXPRO type OCCURS function:

Select * FROM Table1 WHERE OCCURS('Y', FLAGS) > 3

If FLAGS is a VARCHAR(7) and equals "YYYYNNN" then OCCURS would return 4 and the row would return. The database that I am

accessing has >165,000,000 rows and >500 columns per row so you see that I need all the speed I can get!


'
' This is a VB function which works.
' Can this be compiled into a DLL and
' somehow made available to SQL?
'
Public Function OCCURS(expr1 As String, expr2 As String) As Integer
Dim i As Integer
Dim count As Integer
For i = 1 To Len(expr2)
count = count + Abs((Mid(expr2, i, 1) = expr1))
Next
OCCURS = count
End Function