For the following table definitions:

Name                            Null?    Type           Comments
 ------------------------------- -------- ----          ------------------------------------
 ENUM                            NOT NULL NUMBER(4)     ENUM should not exceed a length of 4.
 ENAME                                    CHAR(15)       
 ADDRESS                                  CHAR(25)      ADDRESS should not exceed 25 characters.
 SALARY                                   NUMBER(5)     
 OFFICE                                   CHAR(4)
 DNUM                            NOT NULL NUMBER(4)     Department which this employee belongs to

department

 Name                            Null?    Type          Comments
 ------------------------------- -------- ----          -------------------------------------
 DNUM                            NOT NULL NUMBER(4)
 DMGR                            NOT NULL NUMBER(4)     Department manager
 DNAME                           NOT NULL CHAR(15)

project

 Name                            Null?    Type          Comments
 ------------------------------- -------- ----          -------------------------------------
 PNUM                            NOT NULL NUMBER(4)
 PMGR                            NOT NULL NUMBER(4)     Project manager
 PTITLE                          NOT NULL CHAR(15)

emp_proj

 Name                            Null?    Type
 ------------------------------- -------- ----
 PNUM                            NOT NULL NUMBER(4)
 ENUM                            NOT NULL NUMBER(4)

I have to write SQL query which will find the names of employees who do not share an office but work on the same project, and have different salaries... I've spent last three days trying to figure out something, but no idea as far. I will appreciate any advice.