Hi Please help me compose the query in PostgreSQL. Using PostgreSQL 7.1.2. Suppose relations A and B have columns: {X1, X2, ..., Xm, Y1, Y2, ..., Yn} and {Y1, Y2, ..., Yn} Attributes Y1, Y2, ..., Yn are common for both relations and have the same type in both. How can I define in PostgreSQL the query producing relation with columns X1,X2,...,Xm containing all those tuples satisfying conditon: relation A contains tupple {x1,x2,...xm,y1,y2,...,yn} for _each_ tupple {y1,y2,...,yn} in relation B ? Where x1 denotes particular value of colum X1 etc. For example: consider two tables DEND and DOR. DEND DOR s | p p ----+---- ---- s1 | p1 p1 s1 | p2 p2 s1 | p3 p3 s1 | p4 p4 s1 | p5 p5 s1 | p6 p5 s2 | p1 (6 rows) s2 | p2 s3 | p2 s4 | p2 s4 | p4 s4 | p5 (12 rows) For such tables our desired query should return: s ---- s1 Thanks in advance. -- Vladimir Zolotych [EMAIL PROTECTED] ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])