New to sql

Question

hi
i started learning sql some time ago and have got some expertise over it but when i try to run accept command it does not work on my 8i personal and when i install 8i enterprise on my win 2k NT it ask for net8 host name please help me over it and when i cancel it and run sql it says TNS PROTOCOL ERROR
please help me

Answer 1

Why is it that when I added the following, it says
not a grp by expression.
SELECT i.instructor_id, COUNT(s.course_no),
i.first_name ||','|| i.last_name name, s.SECTION_ID
FROM instructor i, section s
WHERE i.instructor_id = s.instructor_id
GROUP BY i.instructor_id;You can put only grouping columns or aggregates in select clause. Imagine something like this (for simplicity - table after join):
INSTRUCTOR_ID    COURSE_NO   SECTION_ID
aaa                        1                      1
aaa                        2                      3 SELECT instructor_id, COUNT(course_no), section_ID
  FROM table_name
  GROUP BY instructor_id;
results:
AAA        2          ????Which section_id should be returned?