Kenneth,

Sorry, if it's not an answer on your original question, but it seems to me that your code needs a little improvement. See my code under yours...

>> Select * from Customer where cust_ID in (SELECT cust_ID from CurSelectedItems).
>> Same approach DF adviced.
>> HTH
>
>Actually that is different from what DF suggests but you get the idea. David's suggestion is what I want to do.
>What I was doing is in the following code:
>
>

Function fSeekpair
>
>** determine if cPerson_id has bought all the items in ItemsArray
>** Purchase table has an index on cPerson_id+cItem_id.     ItemsArray is an array of cItem_id
>
>Parameters cPerson_id, ItemsArray, nArraySize
>
>Local nCnt, lPairFound
>
>nCnt = 1
>lPairFound = .T.
>	
>Do While nCnt <= nArraysize.AND.lPairFound
>	lPairFound=Seek(cPerson_id+aItemsArray[li,1],'PURCHASE','Person_Item') .AND. lPairFound
>	li=li+1
>EndDo
>
>Return lPairFound

Function fSeekpair

** determine if cPerson_id has bought all the items in ItemsArray
** Purchase table has an index on cPerson_id+cItem_id.     ItemsArray is an array of cItem_id

Parameters cPerson_id, ItemsArray

Local lnCnt, llPairFound, lnArraySize

lnArraySize=alen(ItemsArray,1) && assuming two-dimensional array (code, description)

llPairFound = .T.
	
for lnCnt=1 to lnArraySize 
	llPairFound=Seek(cPerson_id+aItemsArray[lnCnt,1],'PURCHASE','Person_Item')
        if not llPairFound && Person hasn't bought this item
           exit && stop at this point
        endif  
endfor

Return lPairFound

>To get all people who bought the n items in aItemsArray
>
>

Select cPerson_id from PERSONS where fseekpair(cPerson_id,@Itemlist,Itemlistnumber) ;
>                into cursor something

>I will try David's approach since it does look much cleaner but I'm still trying to figure out

I would suggest to try my approach first (using subquery), because you don't need to get additional info about Items, right? If you need to select cPerson_Id only, do it the simplest way: use subQuery.

If you take a look into SQL help, you'd find, that UDF is not a good place for SQL.

>1) Why does this function work when called directly but loses it in the SQL Select

See SQL Help.

>2) Why is this a bad way to do this? What problems can it cause (ED).
>
>Thanks everyone for all the help