How to remove duplicate values from SQL inner join tables? - oracle

Question

I have two tables:
Table 1:
+-----------+-----------+------------------+
| ID | Value | other |
+-----------+-----------+------------------+
| 123456 | 5 | 12 |
| 987654 | 7 | 15 |
| 456789 | 6 | 22 |
+-----------+-----------+------------------+
Table 2:
+-----------+-----------+------------------+
| ID | Type | other |
+-----------+-----------+------------------+
| 123456 | 00 | 2 |
| 123456 | 01 | 6 |
| 123456 | 02 | 4 |
| 987654 | 00 | 7 |
| 987654 | 01 | 8 |
| 456789 | 00 | 6 |
| 456789 | 01 | 16 |
+-----------+-----------+------------------+
Now I perform the inner join:
SELECT
table1.ID, table2.TYPE, table1.value, table2.other
FROM
table1 INNER JOIN table2 ON table1.ID = table2.ID
Here the SQLfiddle
Result Table:
+-----------+-----------+---------+------------------+
| ID | Type | Value | other |
+-----------+-----------+---------+------------------+
| 123456 | 00 | 5 | 2 |
| 123456 | 01 | 5 | 6 |
| 123456 | 02 | 5 | 4 |
| 987654 | 00 | 7 | 7 |
| 987654 | 01 | 7 | 8 |
| 456789 | 00 | 6 | 6 |
| 456789 | 01 | 6 | 16 |
+-----------+-----------+---------+------------------+
This is totally what I expected but not what I need.
Because if I now want to get the Value per ID the Value gets doubled or tripled for the first cause.
Desired Table:
+-----------+-----------+---------+------------------+
| ID | Type | Value | other |
+-----------+-----------+---------+------------------+
| 123456 | 00 | 5 | 2 |
| 123456 | 01 | - | 6 |
| 123456 | 02 | - | 4 |
| 987654 | 00 | 7 | 7 |
| 987654 | 01 | - | 8 |
| 456789 | 00 | 6 | 6 |
| 456789 | 01 | - | 16 |
+-----------+-----------+---------+------------------+
I tried to achieve a similar output by counting the rows per id and dividing the sum of Value by that count but it did not seem to work and is not the desired output.
Also, I tried grouping but this did not seem to achieve the desired output.
One thing to mention is that the DB I am working with is an ORACLE SQL DB.

Answer 1

How about this:
select table1.id
, table2.type
, case
when row_number() over (partition by table1.id order by table2.type) = 1
then table1.value
end as "VALUE"
, table2.other
from table1
join table2 on table1.id = table2.id
order by 1, 2;
(This is Oracle SQL syntax. Your SQL Fiddle (thanks!) was set to MySQL, which as far as I know doesn't have analytic functions like row_number().)

Answer 2

A way to get the result.
select t1.ID,
t2.type,
t1.value,
t2.other
from table1 t1 inner join table2 t2
ON t1.ID = t2.ID
inner join (select ID, min(type) mv
from table2
group by id) m
on t2.id = m.id
and t2.type = m.mv
union all
select t1.ID,
t2type,
null,
t2.other
from table1 t1 inner join table2 t2
ON t1.ID = t2.ID
and not exists (
select 1 from (
select ID, min(type) mv
from table2
group by id) m
where t2.id = m.id
and t2.type = m.mv
)
order by id,type

Answer 3

You can use a CASE block to display NULL for which it is NOT equal to MIN value of type
SELECT table1.ID,
table2.TYPE,
CASE
WHEN table2.TYPE =
MIN (table2.TYPE)
OVER (PARTITION BY table1.id ORDER BY table2.TYPE)
THEN
Table1.VALUE
END
VALUE,
table2.other
FROM table1 INNER JOIN table2 ON table1.ID = table2.ID;