I want to remove all duplicate records except the first one.
Like :
NAME
R
R
rajesh
YOGESH
YOGESH
Now in the above I want to remove the second "R" and the second "YOGESH".
I have only one column whose name is "NAME".
Use a CTE (I have several of these in production).
;WITH duplicateRemoval as (
SELECT
[name]
,ROW_NUMBER() OVER(PARTITION BY [name] ORDER BY [name]) ranked
from #myTable
ORDER BY name
)
DELETE
FROM duplicateRemoval
WHERE ranked > 1;
Explanation: The CTE will grab all of your records and apply a row number for each unique entry. Each additional entry will get an incrementing number. Replace the DELETE with a SELECT * in order to see what it does.
Seems like a simple distinct modifier would do the trick:
SELECT DISTINCT name
FROM mytable
This is bigger code but it works perfectly where you don't take the original row but find all the duplicate Rows
select majorTable.RowID,majorTable.Name,majorTable.Value from
(select outerTable.Name, outerTable.Value, RowID, ROW_NUMBER()
over(partition by outerTable.Name,outerTable.Value order by RowID)
as RowNo from #Your_Table outerTable inner join
(select Name, Value,COUNT(*) as duplicateRows FROM #Your_Table group by Name, Value
having COUNT(*)>1)innerTable on innerTable.Name = outerTable.Name
and innerTable.Value = outerTable.Value)majorTable where MajorTable.ROwNo <>1
Related
I'm trying to make an SQL query that returns the greatest number from a column and its respective id.
For more information I have two columns ID and NUMBER. Both of them have 2 entries and I want to get the highest number with the ID next to it. This is what I tried but didn't success.
SELECT ID, MAX(NUMBER) AS MAXNUMB
FROM TABLE1
GROUP BY ID, MAXNUMB;
The problem I'm experiencing is that it just shows ALL the entries and if I add a "where" expression it just shows the same (all entries [ids+numbers]).
Pd.: Yes, I got what I wanted but only with one column (number) if I add another column (ID) to select it "brokes".
Try:
SELECT
ID,
A_NUMBER
FROM TABLE1
WHERE A_NUMBER = (
SELECT MAX(A_NUMBER)
FROM TABLE1);
Presuming you want the IDs* of the row with the highest number (and not, instead, the highest number for each ID -- if IDs were not unique in your table, for example).
* there may be more than one ID returned if there are two or more IDs with equal maximum numbers
you can try this
Select ID,maxNumber
From
(
SELECT
ID,
(Select Max(NUMBER) from Tmp where Id = t.Id) maxNumber
FROM
Tmp t
)T1
Group By ID,maxNumber
The query you posted has an illegal column name (number) and is group by the alias for the max value, which is illegal and also doesn't make sense; and you can't include the unaliased max() within the group-by either. So it's likely you're actually doing something like:
select id, max(numb) as maxnumb
from table1
group by id;
which will give one row per ID, with the maximum numb (which is the new name I've made up for your numeric column) for each ID. Or as you said you get "ALL the entries" you might have group by id, numb, which would show all rows from the table (unless there are duplicate combinations).
To get the maximum numb and the corresponding id you could group by id only, order by descending maxnumb, and then return the first row only:
select id, max(numb) as maxnumb
from table1
group by id
order by maxnumb desc
fetch first 1 row only
If there are two ID with the same maxnumb then you would only get one of them - and which one is indeterminate unless you modify the order by - but in that case you might prefer to use first 1 row with ties to see them all.
You could achieve the same thing with a subquery and analytic function to generating a ranking, and have the outer query return the highest-ranking row(s):
select id, numb as maxnumb
from (
select id, numb, dense_rank() over (order by numb desc) as rnk
from table1
)
where rnk = 1
You could also use keep to get the same result as first 1 row only:
select max(id) keep (dense_rank last order by numb) as id, max(numb) as maxnumb
from table1
fiddle
I have the following SQL Syntax to delete duplicate rows, but never are any rows affected.
DELETE FROM content_stacks WHERE id NOT IN (
SELECT id
FROM content_stacks
GROUP BY user_id, content_id
);
The subquery itself is returning the id list of first entries correctly.
SELECT id
FROM content_stacks
GROUP BY user_id, content_id
When I'm inserting the results list as a string it is working, too:
DELETE FROM content_stacks WHERE id NOT IN (239,231,217,218,219,232,233,220,230,226,234,235,224,225,221,223,222,227,228,229,236,237,238,216,208,209,210,204,211,212,242,203,240,201,241,205,206,207,213,214,215);
I checked many similar examples and this should be working in my opinion. What am I missing?
First find first rows using ROW_NUMBER Then delete record with row number greater than 1:
WITH CTE AS (
SELECT id , ROW_NUMBER() OVER(PARTITION BY user_id, content_id, ORDER BY id) rn
FROM content_stacks
)
DELETE cs
FROM content_stacks cs
INNER JOIN CTE ON CTE.id = cs.id
WHERE rn > 1
Am sorry to ask but if your deleting why would u need to group the records.
Are not just increasing the runtime.
The code from Meyssam Toluie is not working as it is but I made a similar solution with the same idea with rownumbers:
DELETE FROM content_stacks WHERE id IN
(SELECT id FROM (
SELECT id, ROW_NUMBER() OVER(PARTITION BY user_id, content_id)row_num
FROM content_stacks
) sub
WHERE row_num > 1)
This is working for me now.
My first command did not work because: The group by command does not show all ids in the output, but they are still there, so in fact all ids were returned in the NOT IN id-list. The row number seems to be the easiest way for this problem.
I have a table that look like this:
The problem is I need to get the last record with duplicates in the column "NRODENUNCIA".
You can use MAX(DENUNCIAID), along with GROUP BY... HAVING to find the duplicates and select the row with the largest DENUNCIAID:
SELECT MAX(DENUNCIAID), NRODENUNCIA, FECHAEMISION, ADUANA, MES, NOMBREESTADO
FROM YourTable
GROUP BY NRODENUNCIA, FECHAEMISION, ADUANA, MES, NOMBREESTADO
HAVING COUNT(1) > 1
This will only show rows that have at least one duplicate. If you want to see non-duplicate rows too, just remove the HAVING COUNT(1) > 1
There are a number of solutions for your problem. One is to use row_number.
Note that I've ordered by DENUNCIID in the OVER clause. This defines the "Last Record" as the one that has the largest DENUNCIID. If you want to define it differently you'd need to change the field that is being ordered.
with dupes as (
SELECT
ROW_NUMBER() OVER (Partition by NRODENUNCIA ORDER BY DENUNCIID DESC) RN,
*
FROM
YourTable
)
SELECT * FROM dupes where rn = 1
This only get's the last record per dupe.
If you want to only include records that have dupes then you change the where clause to
WHERE rn =1
and NRODENUNCIA in (select NRODENUNCIA from dupes where rn > 1)
I want to pull all rows except the last one in Oracle SQL
My database is like this
Prikey - Auto_increment
common - varchar
miles - int
So I want to sum all rows except the last row ordered by primary key grouped by common. That means for each distinct common, the miles will be summed (except for the last one)
Note: the question was changed after this answer was posted. The first two queries work for the original question. The last query (in the addendum) works for the updated question.
This should do the trick, though it will be a bit slow for larger tables:
SELECT prikey, authnum FROM myTable
WHERE prikey <> (SELECT MAX(prikey) FROM myTable)
ORDER BY prikey
This query is longer but for a large table it should faster. I'll leave it to you to decide:
SELECT * FROM (
SELECT
prikey,
authnum,
ROW_NUMBER() OVER (ORDER BY prikey DESC) AS RowRank
FROM myTable)
WHERE RowRank <> 1
ORDER BY prikey
Addendum There was an update to the question; here's the updated answer.
SELECT
common,
SUM(miles)
FROM (
SELECT
common,
miles,
ROW_NUMBER() OVER (PARTITION BY common ORDER BY prikey DESC) AS RowRank
FROM myTable
)
WHERE RowRank <> 1
GROUP BY common
Looks like I am a little too late but here is my contribution, similar to Ed Gibbs' first solution but instead of calculating the max id for each value in the table and then comparing I get it once using an inline view.
SELECT d1.prikey,
d1.authnum
FROM myTable d1,
(SELECT MAX(prikey) prikey myTable FROM myTable) d2
WHERE d1.prikey != d2.prikey
At least I think this is more efficient if you want to go without the use of Analytics.
query to retrieve all the records in the table except first row and last row
select * from table_name
where primary_id_column not in
(
select top 1 * from table_name order by primary_id_column asc
)
and
primary_id_column not in
(
select top 1 * from table_name order by primary_id_column desc
)
I need, if possible, a t-sql query that, returning the values from an arbitrary table, also returns a incremental integer column with value = 1 for the first row, 2 for the second, and so on.
This column does not actually resides in any table, and must be strictly incremental, because the ORDER BY clause could sort the rows of the table and I want the incremental row in perfect shape always.
The solution must run on SQL Server 2000
For SQL 2005 and up
SELECT ROW_NUMBER() OVER( ORDER BY SomeColumn ) AS 'rownumber',*
FROM YourTable
for 2000 you need to do something like this
SELECT IDENTITY(INT, 1,1) AS Rank ,VALUE
INTO #Ranks FROM YourTable WHERE 1=0
INSERT INTO #Ranks
SELECT SomeColumn FROM YourTable
ORDER BY SomeColumn
SELECT * FROM #Ranks
Order By Ranks
see also here Row Number
You can start with a custom number and increment from there, for example you want to add a cheque number for each payment you can do:
select #StartChequeNumber = 3446;
SELECT
((ROW_NUMBER() OVER(ORDER BY AnyColumn)) + #StartChequeNumber ) AS 'ChequeNumber'
,* FROM YourTable
will give the correct cheque number for each row.
Try ROW_NUMBER()
http://msdn.microsoft.com/en-us/library/ms186734.aspx
Example:
SELECT
col1,
col2,
ROW_NUMBER() OVER (ORDER BY col1) AS rownum
FROM tbl
It is ugly and performs badly, but technically this works on any table with at least one unique field AND works in SQL 2000.
SELECT (SELECT COUNT(*) FROM myTable T1 WHERE T1.UniqueField<=T2.UniqueField) as RowNum, T2.OtherField
FROM myTable T2
ORDER By T2.UniqueField
Note: If you use this approach and add a WHERE clause to the outer SELECT, you have to added it to the inner SELECT also if you want the numbers to be continuous.