Updating row, according to Rownum in Oracle - oracle

Question

I have two tables in Oracle
TableProducts
Product_Code, and 20 others fields
BGU
LSO
MPA
MPA4
MPA5
TPA
UGU
For this example, now I have 7 values, but maybe 9 values later.
CREATE TABLE TableContacts AS SELECT *
FROM Contacts
WHERE Rownum <= (4*(SELECT Count(Distinct Product_Code) FROM TableProducts));
Now I have 28 Rows in my TableContacts.
Now I need To UPDATE the rows in order to create combinations test.
TableContacts
Product_Code, Email, PDF, and 17 others fields.
Email and PDF has two possible values 'N' or 'Y'.
I need to fill the TableContacts with the combinations of Product_Code, Email and PDF fields, according to Rownum position.
Rownum = 1 -> Product_Code='BGU', Email='N', PDF='N'
Rownum = 2 -> Product_Code='BGU', Email='N', PDF='Y'
Rownum = 3 -> Product_Code='BGU', Email='Y', PDF='N'
Rownum = 4 -> Product_Code='BGU', Email='Y', PDF='Y'
Rownum = 5 -> Product_Code='LSO', Email='N', PDF='N'
If I have 7 values for Product_Code, 2 by Email and 2 by PDF, then I will need to fill (7 * 2 *2) = 28 Rows.
How to create and SQL for this situation updating TableContacts?

Answer 1

Partially, requirement doesn't make sense. Rows in a table within the relational databases aren't sorted in any way, so - saying that you want to refer to a rownum is ... strange. That's why I modified the contacts table and added yet another column - rn - which shows that rownum of yours.
Also, this example shows only 3 products (didn't feel like typing all of them). Code that follows doesn't care about number of those products and will work the same regardless.
Products:
SQL> select * From products;
CODE
-----
BGU
LSO
MPA
Insert into Contacts:
SQL> insert into contacts (rn, code, email, pdf)
2 with temp as
3 (select p.code, x.lvl
4 from products p cross join (Select level lvl from dual connect by level <= 4) x
5 )
6 select t.lvl,
7 t.code,
8 case when t.lvl in (1, 2) then 'N'
9 when t.lvl in (3, 4) then 'Y'
10 end email,
11 --
12 case when t.lvl in (1, 3) then 'N'
13 when t.lvl in (2, 4) then 'Y'
14 end pdf
15 from temp t;
12 rows created.
Result:
SQL> select * From contacts
2 order by code, rn;
RN CODE E P
---------- ----- - -
1 BGU N N
2 BGU N Y
3 BGU Y N
4 BGU Y Y
1 LSO N N
2 LSO N Y
3 LSO Y N
4 LSO Y Y
1 MPA N N
2 MPA N Y
3 MPA Y N
4 MPA Y Y
12 rows selected.
SQL>
[EDIT: how to update table that contains rows?]
If I understood you correctly, this is what you initially have in the CONTACTS table:
SQL> select code, rownum from contacts;
CODE ROWNUM
----- ----------
BGU 1
LSO 2
MPA 3
BGU 4
LSO 5
MPA 6
BGU 7
LSO 8
MPA 9
BGU 10
LSO 11
MPA 12
12 rows selected.
SQL>
As I previously said: rownum is irrelevant here, it can change, you can't tell which rownum belongs to which code.
Anyway, such an update (merge, actually) does the job:
SQL> merge into contacts a
2 using (select c.code,
3 c.rowid,
4 row_number() over (partition by c.code order by null) rn
5 from contacts c
6 ) x
7 on (a.rowid = x.rowid)
8 when matched then update set
9 a.email = case when x.rn in (1, 2) then 'N'
10 when x.rn in (3, 4) then 'Y'
11 end,
12 a.pdf = case when x.rn in (1, 3) then 'N'
13 when x.rn in (2, 4) then 'Y'
14 end;
12 rows merged.
SQL> select * From contacts order by code, email, pdf;
CODE EMAIL PDF
----- ----- -----
BGU N N
BGU N Y
BGU Y N
BGU Y Y
LSO N N
LSO N Y
LSO Y N
LSO Y Y
MPA N N
MPA N Y
MPA Y N
MPA Y Y
12 rows selected.
SQL>