Re: rewriting query without using UNION

from basic set theory:

union = OR
intersect = AND

 select e.id, e.name, d.deptname from emp e, dept d  where e.deptno=d.deptno and e.name='JOSE' or d.deptno = 50;  

>
> From: "Linda Wang" <lwang344_at_hotmail.com>
> Date: 2003/10/29 Wed PM 12:54:26 EST
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> Subject: rewriting query without using UNION
>
> Hi,
> I wonder if there's a better way of writing the query below. Basically, I
> would like to return employee records where employee name='JOSE' + all
> employees in deptno=50. My query can have multiple 'OR' criterias where the
> next criteria maybe returning all employees with salary>60000 in addition to
> the above two criterias. Building the query with multiple UNIONs will
> definitely degrade the query performance. Is there a better way of rewriting
> the query?
>
> Thanks!
>
> linda
>
> select e.id, e.name, d.deptname from emp e, dept d
> where e.deptno=d.deptno and e.name='JOSE'
> union
> select e.id, e.name, d.deptname from emp e, dept d
> where e.deptno=d.deptno and d.deptno=50;
>
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> Author: Linda Wang
> INET: lwang344_at_hotmail.com
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