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                         gsmith@eurocom.od.ua

Sun, 02 Sep 2001 11:23:23 +0300
"Vladimir V. Zolotych" <gsmith@eurocom.od.ua>
Need help in composing PostgreSQL query