Here is my solution taken from the help of you all:

CLEAR
SET EXACT On
partnoS = ""
partnoS2 = ""
recseqS2 = ""
lcString = ""

SELECT testQuery

lcString = ""
SCAN

IF NOT ALLTRIM(testQuery.partno) == partnoS Then
IF NOT RIGHT(recseqS2,2) == ")," Then
recseqS2 = SUBSTR(recseqS2,1,LEN(recseqS2)-2)
recseqS2 = recseqS2 + "),"
EndIf
lcString = "),"
recseqS2 = recseqS2 + ALLTRIM(testQuery.partno) + "("+recseq+lcString

ELSE
IF RIGHT(recseqS2,2) == ")," Then
recseqS2 = SUBSTR(recseqS2,1,LEN(recseqS2)-2)
recseqS2 = recseqS2 + ","
EndIf
lcString = ","
recseqS2 = recseqS2 + recseq+lcString
ENDIF
partnoS = ALLTRIM(testQuery.partno)

ENDSCAN
recseqS2 = SUBSTR(recseqS2,3,LEN(recseqS2))
recseqS2 = SUBSTR(recseqS2,1,LEN(recseqS2)-1)
recseqS2 = recseqS2 + ")"
? recseqS2