Hi, dear experts: Assume that a tuple is composed of <,,...,, Value>. IF AK is stored in Field A, BK is stored in Field B, CK is stored in Field C (1<=K<=N), so there are N A fields,N B fields and N C fields. The question is if I want to query whith the condition of , how can i get the exact value correspoding to . longing for your helps Thanks in advance. 2011-04-01 Yuan Wu [GMail]