my table include only two columns, My purpose ranking no columns and add to new column
no foto
1 foto1
1 foto2
2 foto3
2 foto4
2 foto5
3 foto6
3 foto7
I want to do like below table
no foto newcolomn
1 foto1 1
1 foto2 2
2 foto3 1
2 foto4 2
2 foto5 3
3 foto6 1
3 foto7 2
You can use row_number():
select no, foto, row_number() over(partition by no order by foto) newcolumn
from mytable
Related
I wonder how to update order in this table for many-to-many relationship using SQL based on PostsId.
So my table now looks like:
I'm using SQL Server
BlogsId
PostsId
Order
1
1
1
0
2
2
1
0
3
3
2
0
3
4
2
0
3
5
3
0
3
6
3
0
but I want to update Order using SQL to this:
BlogsId
PostsId
Order
1
1
1
1
2
2
1
2
3
3
2
1
3
4
2
2
3
5
3
1
3
6
3
2
So for example: Blog with Id 3 is the first blog in Post with Id 2, Blog with Id 4 is the second Blog in Post with Id 2 and etc...
I've tried this:
DECLARE #myVar int
SET #myVar = 0
UPDATE [dbo].[BlogPost]
SET #myVar = [Order] = #myVar + 1
but then I got this:
BlogsId
PostsId
Order
1
1
1
1
2
2
1
2
3
3
2
3
3
4
2
4
3
5
3
5
3
6
3
6
So, I think I should do something in WHERE part (with Distinct maybe) but I don't know exactly what. I could write something in C# to do what I want but I don't know how to write something like this in SQL.
Physically maintaining an order or sequence of rows is rarely a good idea and can lead to data inconsistencies and other unforseen issues.
You would be better off creating a view that provides the additional Order column which you can do using row_number()
Create view BlogPosts as
select *,
Row_Number() over(partition by PostsId order by BlogsId) as [Order]
from blogpost;
If you really want to update an actual column in the table you could use a CTE
with b as (
select *,
Row_Number() over(partition by PostsId order by BlogsId) as seq
from blogpost
)
update b
set [Order] = seq;
You can update from a calculated row_number.
update t
set [Order] = rn
from (
select BlogsId, PostsId, [Order]
, rn = row_number() over (partition by PostsId order by BlogsId asc)
from BlogPost
) t
where ([Order] is null or [Order]!=rn);
select *
from BlogPost
order by BlogsId, PostsId
BlogsId
PostsId
Order
1
1
1
2
1
2
3
2
1
4
2
2
5
3
1
6
3
2
Demo on db<>fiddle here
1.I have data as follows (just a subset - there are 20K records)
sku,id
1 1
1 2
1 2
1 2
1 3
1 4
1 1
1 2
1 3
1 4
1 4
1 4
1 5
1 6
1 6
2 1
2 1
2 2
2 3
2 3
2 3
2 4
2 4
2 5
2 5
2 6
2 7
2 1
2 2
2 3
The above values translate to
1 = 4 records
1 = 6 records
2 = 7 records
2 = 3 records
The MAX would just give me 6 for one and 7 for 2
The actual total is 1 = 10 and 2 = 10
How do I sum up to get the correct values?
You can use order by and some way of limiting rows. In standard SQL this would be:
select t.*
from t
order by id desc
fetch first 2 rows only;
However, some databases might use limit or select top or some other method.
No handling of ties here. Thousands of other questions handle this topic.
select sku, id
from (
select *, row_number() over (order by id desc) rn
from T
) t
where rn <= 2
order by rn desc;
I have a table of list items. There is a ListID column used as an identifier to group the list items together. Is there a sane way to give every item a sort order, starting at 0 per list and incremental by one per item.
Basically, I need to populate the following SortOrder Column values for a large number of entries/ListIDs.
ID ListID SortOrder
1 1 0
2 0 0
3 1 1
4 0 1
5 1 2
6 0 2
7 2 0
8 2 1
9 2 2
You can use ROW_NUMBER() with a PARTITION on the ListId field for this:
Select Id, ListId,
Row_Number() Over (Partition By ListId Order By Id) -1 As SortOrder
From YourTable
Order By Id
I think you want:
WITH toupdate as (
SELECT t.*,
ROW_NUMBER() OVER (PARTITION BY ListId Order By id) as new_SortOrder
FROM tableName
)
UPDATE toupdate a
SET sortorder = new_sort_order;
SQL Server has the nice ability to update a subquery or CTE under some circumstances.
Do you need to persist the order of lists containing items that are shared between lists? If so, perhaps variations on this schema would work for you.
Item
id label
1 A
2 B
3 C
4 D
List
id listName
1 abc list
2 cbd list
3 aaa list
ListMembership
id listId itemId order
1 1 1 1
2 1 2 2
3 1 3 3
4 2 2 2
5 2 3 1
6 2 4 3
7 3 1 1
8 3 1 2
9 3 1 3
usage:
select i.label from listMembership as lm
join Item as i on i.id=lm.itemId
where lm.listId=2
order by lm.order
yields:
label
C
B
D
The following is an example of what I have to work with.
Sample data :
ID RANK
---------
1 2
1 3
2 4
2 1
3 2
2 3
4 2
SQLFiddle
I am trying to combine the rows with like IDs and sum the RANKs for these IDs into a single row:
ID SUM(rank)
1 5
2 8
3 2
4 2
You can use sum aggregate function together with the group by clause:
select [ID]
, sum([RANK])
from [STUFF]
group by [ID]
SQLFiddle
I am working on a query for SQL Server 2005 that needs to return data with two 'index' fields. The first index 't_index' should increment every time the 'shade' column changes, whilst the second index increments within the partition of the values in the 'shade' column:
t_index s_index shade
1 1 A
1 2 A
1 3 A
1 4 A
1 5 A
2 1 B
2 2 B
2 3 B
2 4 B
2 5 B
To get the s_index column I am using the following:
Select ROW_NUMBER() OVER(PARTITION BY [shade] ORDER BY [shade]) as s_index
My question is how to get the first index to only increment when the value in the 'shade' column changes?
That can be accomplished with the DENSE_RANK() function:
DENSE_RANK() OVER(Order By [shade]) as t_index
You can try to use DENSE_RANK() for that:
SELECT
shade,
s_index = ROW_NUMBER() OVER(PARTITION BY [shade] ORDER BY [shade]),
t_index = DENSE_RANK() OVER (ORDER BY [shade])
FROM dbo.YourTableNameHEre
Gives output:
shade s_index t_index
A 1 1
A 2 1
A 3 1
A 4 1
A 5 1
B 1 2
B 2 2
B 3 2
B 4 2
B 5 2