Yurttas/PL/DBL/mssql/F/01/SPJ/q04.sql

 1/*
 2REM
 3REM q04.sql
 4REM
 5REM Get supplier numbers for suppliers who supply
 6REM the same part to all projects.
 7REM
 8*/
 9
10SELECT S.sn
11FROM Suppliers S
12WHERE EXISTS 
13        (SELECT *
14         FROM Parts P
15         WHERE NOT EXISTS 
16                     (SELECT *
17                      FROM Projects J
18                      WHERE NOT EXISTS 
19                                  (SELECT *
20                                   FROM Shipments SPJ
21                                   WHERE SPJ.sn = S.sn
22                                     AND SPJ.pn = P.pn
23                                     AND SPJ.jn = J.jn)));