Add or delete repeated row - sql

Question

I have an output like this:
id name date school school1
1 john 11/11/2001 nyu ucla
1 john 11/11/2001 ucla nyu
2 paul 11/11/2011 uft mit
2 paul 11/11/2011 mit uft
I would like to achieve this:
id name date school school1
1 john 11/11/2001 nyu ucla
2 paul 11/11/2011 mit uft
I am using direct join as in:
select distinct
a.id, a.name,
b.date,
c.school
a1.id, a1.name,
b1.date,
c1.school
from table a, table b, table c,table a1, table b1, table c1
where
a.id=b.id
and...
Any ideas?

Answer 1

We will need more information such as what your tables contain and what you are after.
One thing I noticed is you have a school and then school1. 3nf states that you should never duplicate fields and append numbers to them to get more information even if you think that the relationship will only be 1 or 2 additional items. You need to create a second table that stores a user associated with 1 to many schools.

Answer 2

I agree with everyone else that both your source table and your desired output are poor design. While you probably can't do anything about your source table, I recommend the following code and output:
Select id, name, date, school from MyTable;
union
Select id, name, date, school1 from MyTable;
(repeat as necessary)
This will give you results in the format:
id name date school
1 john 11/11/2001 nyu
1 john 11/11/2001 ucla
2 paul 11/11/2011 mit
2 paul 11/11/2011 uft
(Note: in my version of SQL, union queries automatically select distinct records so the distinct flag isn't needed)
With this format, you could easily count the number of schools per student, number of students per school, etc.
If processing time and/or storage space is a factor here, you could then split this into 2 tables, 1 with the id,name & date, the other with the id & school (basically what JonH just said). But if you're just working up some simple statistics, this should suffice.

Answer 3

This problem was just too irresistable, so I just took a guess at the data structures that we are dealing with. The technology wasn't specified in the question. This is in Transact-SQL.
create table student
(
id int not null primary key identity,
name nvarchar(100) not null default '',
graduation_date date not null default getdate(),
)
go
create table school
(
id int not null primary key identity,
name nvarchar(100) not null default ''
)
go
create table student_school_asc
(
student_id int not null foreign key references student (id),
school_id int not null foreign key references school (id),
primary key (student_id, school_id)
)
go
insert into student (name, graduation_date) values ('john', '2001-11-11')
insert into student (name, graduation_date) values ('paul', '2011-11-11')
insert into school (name) values ('nyu')
insert into school (name) values ('ucla')
insert into school (name) values ('uft')
insert into school (name) values ('mit')
insert into student_school_asc (student_id, school_id) values (1,1)
insert into student_school_asc (student_id, school_id) values (1,2)
insert into student_school_asc (student_id, school_id) values (2,3)
insert into student_school_asc (student_id, school_id) values (2,4)
select
s.id,
s.name,
s.graduation_date as [date],
(select max(name) from
(select name,
RANK() over (order by name) as rank_num
from school sc
inner join student_school_asc ssa on ssa.school_id = sc.id
where ssa.student_id = s.id) s1 where s1.rank_num = 1) as school,
(select max(name) from
(select name,
RANK() over (order by name) as rank_num
from school sc
inner join student_school_asc ssa on ssa.school_id = sc.id
where ssa.student_id = s.id) s2 where s2.rank_num = 2) as school1
from
student s
Result:
id name date school school1
--- ----- ---------- ------- --------
1 john 2001-11-11 nyu ucla
2 paul 2011-11-11 mit uft