Hi guys, i have a new question about how to simplify a query. I have the tables area_course(cd_area,cd_course) and teacher_course(cd_teacher,cd_course) and a set of pairs of values {(1,2),(98,45),(11,0),...}.
Now, i must to select the areas which courses appears in teacher_course and match with the set of pairs. Something like :
select cd_area from area a1 where
exists (select * from teacher_course c2 where c2.cd_course = a1.cd_course and c2.cd_teacher = 1 and c2.cd_course = 2) and
exists (select * from teacher_course c2 where c2.cd_course = a1.cd_course and c2.cd_teacher = 98 and c2.cd_course = 45) and
exists (select * from teacher_course c2 where c2.cd_course = a1.cd_course and c2.cd_teacher = 11 and c2.cd_course = 0) and
....
This is just a sample. The whole query is giant and its use other tables/columns. Is there a best way to write this query ?
Can you try this query ? :
select cd_area from area a1
join teacher_course c2 using (cd_course)
where (cd_teacher,cd_course) in (select 1,2 union select 98,45 union select 11,0);
Regards, Tomasz Myrta
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