Information Systems ppl please help

who-me · May 12, 2001, 12:55pm

Here is a query:

SELECT DISTINCT J#
FROM SPJ SPJX
WHERE NOT EXISTS
( SELECT *
FROM SPJ SPJY
WHERE EXISTS
( SELECT *
FROM SPJ SPJA
WHERE SPJA.S’# = ‘S1’
AND SPJA.P# = SPJY.P# )
AND NOT EXISTS
( SELECT *
FROM SPJ SPJB
WHERE SPJB.S# = ‘S1’
AND SPJB.P# = SPJY.P#
AND SPJB.J# = SPJX.J# ) ) ;

Run on a relation called SPJ (Suppliers Parts projects)…meaning which suppliers provide which parts to which project

so it had S#,P#,J#,qty attributes… What the ^%@#$&#$%*@&# does this query return??

All projects where supplier s1 supplies all the parts to that project??

http://www3.pak.org/gupshup/smilies/frusty.gif

The_Fish · May 13, 2001, 1:28am

who—me, that’s some query

http://www3.pak.org/gupshup/smilies/pagal.gif

I’ll try solving it (but I am quite certain I’ve forgotten most of what I studied a few months back :hehe

http://www3.pak.org/gupshup/smilies/smile.gif

… and will get back to you.

who-me · May 13, 2001, 6:13am

while yur at it try:

SELECT DISTINCT J#
FROM SPJ SPJX
WHERE NOT EXISTS
( SELECT *
FROM SPJ SPJY
WHERE EXISTS
( SELECT *
FROM SPJ SPJA
WHERE SPJA.S# = SPJY.S1
AND SPJA.P# IN
( SELECT P# FROM P
WHERE COLOR = ‘Red’ )
AND NOT EXISTS
( SELECT *
FROM SPJ SPJB
WHERE SPJB.S# = SPJY.S#
AND SPJB.J# = SPJX.J# ) ) ) ;

too…

http://www3.pak.org/gupshup/smilies/frown.gif

…P is the parts entity..p# is the part number.

[This message has been edited by who—me (edited May 13, 2001).]