I have a table called TABLE_SCREW where I want to get the latest records for each code.
For example, in the table below you should obtain the records with ids 3 and 7.
I am a newbie in sql and I hope you can help me.
You could use:
SELECT TOP 1 WITH TIES *
FROM TABLE_SCREW
ORDER BY ROW_NUMBER() OVER(PARTITION BY CODE ORDER BY Date DESC);
Another approach(may have better performance):
SELECT * -- here * should be replaced with actual column names
FROM (SELECT *,ROW_NUMBER() OVER(PARTITION BY CODE ORDER BY Date DESC) AS rn
FROM TABLE_SCREW) sub
WHERE sub.rn = 1;
Related
Hopefully, someone can help me...
I'm trying to get the last two values from a row_number() window function. Let's say my results contain row numbers up to 6, for example. How would it be possible to get the rows where the row number is 5 and 6?
Let me know if it can be done with another window function or in another way.
Kind regards,
Using QUALIFY:
SELECT *
FROM tab
QUALIFY ROW_NUMBER() OVER(ORDER BY ... DESC) <= 2;
This approach could be further extended to get two rows per each partition:
SELECT *
FROM tab
QUALIFY ROW_NUMBER() OVER(PARTITION BY ... ORDER BY ... DESC) <= 2;
You can use top with order by desc like:
select top 2 row_number() over([partition by] [order by]) as rn
from table
order by rn desc
I'd say #Shmiel is the formal and elegant way, just in case, would be the same as :
WITH CTE AS
(SELECT product,
user_id,
ROW_NUMBER() OVER (PARTITION BY user_id order by product desc)
as RN
FROM Mytable)
SELECT product, user_id
FROM CTE
WHERE RN < 3;
You will use order by [order_condition] with "desc". And then you will use RN(row number) to select as many rows as you want
I have a table as shown in the image.In Number column, the values are appeared more than once (for example 63 appeared twice). I would like to keep only one value. Please see my code:
delete from t1 where
(SELECT *,row_number() OVER (
PARTITION BY
Number
ORDER BY
Date) as rn from t1 where rn > 1)
It shows error. Can anyone please assist.
enter image description here
The column created by row_number() was not accessed by your main query, in order to enable that, you can create a quick sub query and use the desired filter
SELECT *
FROM
(
SELECT *,
row_number() OVER (PARTITION BY Number ORDER BY Date) as rn
FROM t1 ) T
where rn = 1;
The partition by determines how row numbers repeat. The row numbers are assigned per group of partition by keys. So, you can get duplicates.
If you want a unique row number over all rows, just leave out the partition by:
select t1.*
from (select t1.*,
row_number() over (order by date) as rn
from t1
) t1
where rn > 1
if you want to keep only one value, rn = 1 instead of "> 1"
I think this is a simple problem but I cannot find an easy answer. I need to retrieve the last 2 entries by date. I have used max() to get the latest date; but do not know how to retrieve the next most recent.
The stored procedure code for latest date is:
SELECT *
FROM Table
WHERE Date=(SELECT MAX(Date) FROM Table);
So using a separate procedure how do I get the next most recent?
You can use order by and top:
select top 2 t.*
from t
order by date desc;
Or just to get the next most recent only as you stated...thus returning only one row...
select top 1 t.*
from t
where t.date != (select max(date) from table)
order by date desc;
or...
with cte as(
select
t.*
,row_number() over (order by t.date desc) as RN
from table t)
select *
from cte
where RN = 2
OK, I'm a little outta practice on SQL Queries here, I have a table with thousands of entries.
Each row has a unique Id but there is a column named EquipmentId which is not unique and would be present in several rows. I want to return 3 rows for every EquipmentId and if there is less the than 3 entries for an EquipmentID I want those too. ..... make sense ? thanks in advance.
Use ROW_NUMBER() + CTE
;WITH CTE AS(
SELECT *,
ROW_NUMBER() OVER ( PARTITION BY EquipmentId ORDER BY ID ) RN
FROM TableName
)
SELECT *
FROM CTE
WHERE RN <= 3
ORDER BY EquipmentId
Using subqueries you can do it like this:
SELECT *
FROM
(SELECT *, Rank()
OVER
(PARTITION BY equipmentid
ORDER BY ID) Rank
FROM stack) AS a
WHERE
rn <= 3
I'm working on a small project in which I'll need to select a record from a temporary table based on the actual row number of the record.
How can I select a record based on its row number?
A couple of the other answers touched on the problem, but this might explain. There really isn't an order implied in SQL (set theory). So to refer to the "fifth row" requires you to introduce the concept
Select *
From
(
Select
Row_Number() Over (Order By SomeField) As RowNum
, *
From TheTable
) t2
Where RowNum = 5
In the subquery, a row number is "created" by defining the order you expect. Now the outer query is able to pull the fifth entry out of that ordered set.
Technically SQL Rows do not have "RowNumbers" in their tables. Some implementations (Oracle, I think) provide one of their own, but that's not standard and SQL Server/T-SQL does not. You can add one to the table (sort of) with an IDENTITY column.
Or you can add one (for real) in a query with the ROW_NUMBER() function, but unless you specify your own unique ORDER for the rows, the ROW_NUMBERS will be assigned non-deterministically.
What you're looking for is the row_number() function, as Kaf mentioned in the comments.
Here is an example:
WITH MyCte AS
(
SELECT employee_id,
RowNum = row_number() OVER ( order by employee_id )
FROM V_EMPLOYEE
ORDER BY Employee_ID
)
SELECT employee_id
FROM MyCte
WHERE RowNum > 0
There are 3 ways of doing this.
Suppose u have an employee table with the columns as emp_id, emp_name, salary. You need the top 10 employees who has highest salary.
Using row_number() analytic function
Select * from
( select emp_id,emp_name,row_number() over (order by salary desc) rank
from employee)
where rank<=10
Using rank() analytic function
Select * from
( select emp_id,emp_name,rank() over (order by salary desc) rank
from employee)
where rank<=10
Using rownum
select * from
(select * from employee order by salary desc)
where rownum<=10;
This will give you the rows of the table without being re-ordered by some set of values:
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT '1')) AS RowID, * FROM #table
If using SQL Server 2012 you can now use offset/fetch:
declare #rowIndexToFetch int
set #rowIndexToFetch = 0
select
*
from
dbo.EntityA ea
order by
ea.Id
offset #rowIndexToFetch rows
fetch next 1 rows only