This is hard to explain so I will give an example.
I need SQL (ms server), I assume its with row_number over partition but can't get it to work.
I have this table:
ID
PreviousID
Data
1
a
2
1
b
3
2
c
4
d
5
4
e
6
f
I want these results:
ID
NewID
Data
1
1
a
2
1
b
3
1
c
4
2
d
5
2
e
6
3
f
And another with just the new IDs of each sequence:
NewID
Data
1
a
2
d
3
f
Instead of a row number new id, it could also have the first id of the sequence, whatever is easier, as long as it identifies the sequence.
Seems you want a windowed COUNT of rows where the value of PreviousID is NULL.
SELECT ID,
COUNT(CASE WHEN PreviousID IS NULL THEN 1 END) OVER (ORDER BY ID) AS NewID,
Data
FROM dbo.YourTable;
I'm trying to figure out SQL query that will list only one to many relation
Below Table contain 11 records where i would like to return two line with Field1 = 7 (one to many)
Table1:
Field1 Field2
1 a
2 a
3 b
4 b
5 c
4 d exclude 4 and 6 as d is linked to both
6 d
6 e
7 f One to Many
7 j One to Many
8 g
You want all the field2 values to appear once for each field1. Here is a method using window functions:
select field1
from (select t.*,
count(*) over (partition by field2) as num_field2
from t
) t
group by field1
having count(*) > 1 and max(num_field2) = 1;
So I've been trying to change the order of rows according to my own logic.
Let's say I have a set of numbers from 1 to 4. If the rows have n entries of different values from 1 to 4 and I want to rearrange all the rows such that I have only rows with 4 at the top followed by a grouped combination of two 2's and a 1, followed by the 3's.
How can it be done using Sql server?
ID ROWS --> ID NEW ORDER
-- ---- -- ---------
A 1 G 4
B 1 G 4
C 2 G 4
C 2 G 4
D 2 C 2
D 2 C 2
E 2 A 1
E 2 E 2
F 3 E 2
F 3 B 1
F 3 D 2
G 4 D 2
G 4 F 3
G 4 F 3
G 4 F 3
Code till now:
SELECT * FROM table
ORDER BY
CASE
WHEN ROW = 4 THEN '1'
WHEN ROW = 1 THEN '2'
WHEN ROW = 2 THEN '3'
WHEN ROW = 3 THEN '4'
END ASC
Assuming ROWS is exactly the number of rows with a paticular ID,
order the rows first by a group according to ROWS interval (4),(1..2), (all the rest) then within the second group row_number() sequences of IDs having ROWS = 1 and 2 independently. Within the same sequence number order by ROWS reverse order.
select ID, ROWS
from (
select *
, case when ROWS = 4 then 1
when ROWS between 1 and 2 then 2
else 3 end grp1
, row_number() over(partition by ROWS order by ROWS) - row_number() over(partition by ROWS, ID order by ID) pos2
from yourtable) t
order by grp1, case ROWS when 1 then pos2 else pos2/2 end, -ROWS, ID
If you want you can try doing it using order by clause. You can use your logic to sort values accordingly. Default order by ASC. So i have tried below query with order by if this gives you some idea of doing it:
select id from test order by case when id%2 = 0 then id end desc
Will give;
ID
8
6
4
5
So you can try ordering with some logic inside.
I am trying to update a column in a table so that the Index column (which is currently arbitrary numbers) is renumbered sequentially starting at 1000 with increments of 10, and this sequence restarts every time the Group changes.
I have tried ROWNUMBER() with PARTITION and trying to define a SEQUENCE, but I can't seem to get the result I'm looking for.
Table 1
ID Group Index
1 A 1
2 A 2
3 B 3
4 B 4
5 B 5
6 C 6
7 D 7
What I want:
Table 1
ID Group Index
1 A 1000
2 A 1010
3 B 1000
4 B 1010
5 B 1020
6 C 1000
7 D 1000
You can use row_number() with some arithmetic:
select t.*,
990 + 10 * row_number() over (partition by group order by id) as index
from t;
Note that group and index are SQL reserved words, so they are really bad column names.
My SQL query returns results with 4 columns "A", "B", "C", "D".
Suppose the results are:
A B C D
1 1 1 1
1 1 1 2
2 2 2 1
Is it possible to get the count of duplicate rows with columns "A", "B", "C" in each row.
e.g. the expected result is:
A B C D cnt
1 1 1 1 2
1 1 1 2 2
2 2 2 1 1
I tried using count(*) over. But it returns me the total number of rows returned by the query.
Another information is that in example I have mentioned only 3 columns based on which I need to check the count. But my actual query has such 8 columns. And number of rows in database are huge. So I think group by will not be a feasible option here.
Any hint is appreciable.
Thanks.
Maybe too late, but probably the count over as analytic function (aka window function) within oracle helps you. When I understand your request correctly, this should solve your problem :
create table sne_test(a number(1)
,b number(1)
,c number(1)
,d number(1)
,e number(1)
,f number(1));
insert into sne_test values(1,1,1,1,1,1);
insert into sne_test values(1,1,2,1,1,1);
insert into sne_test values(1,1,2,4,1,1);
insert into sne_test values(1,1,2,5,1,1);
insert into sne_test values(1,2,1,1,3,1);
insert into sne_test values(1,2,1,2,1,2);
insert into sne_test values(2,1,1,1,1,1);
commit;
SELECT a,b,c,d,e,f,
count(*) over (PARTITION BY a,b,c)
FROM sne_test;
A B C D E F AMOUNT
-- -- -- -- -- -- ------
1 1 1 1 1 1 1
1 1 2 4 1 1 3
1 1 2 1 1 1 3
1 1 2 5 1 1 3
1 2 1 1 3 1 2
1 2 1 2 1 2 2
2 1 1 1 1 1 1
To find duplicates you must group the data based on key column
select
count(*)
,empno
from
emp
group by
empno
having
count(*) > 1;
This allows you to aggregate by empno even when multiple records exist for each category (more than one).
You have to use a subquery where you get the count of rows, grouped by A, B and C. And then you join this subquery again with your table (or with your query), like this:
select your_table.A, your_table.B, your_table.C, your_table.D, cnt
from
your_table inner join
(SELECT A, B, C, count(*) as cnt
FROM your_table
GROUP BY A, B, C) t
on t.A = your_table.A
and t.B = your_table.B
and t.C = your_table.C