I got duplicates by using the below query
select candidateid
from table1 table with(nolock)
where status in (1,0)
group by candidateid, bgvtype, DepartmentId, BUId, CustomerId, ProjectId
having
COUNT(candidateid)>1 and COUNT(bgvtype)>1 and
COUNT(DepartmentId)>1 and COUNT(BUId)>1 and
COUNT(CustomerId)>1 and COUNT(ProjectId)>1
And I got the below result when I exec
select * from table1 where candidateid=?
I should ignore 1st record since its project id is different and I need all other records for Ref. I have given one candidate id in the image but in table we have a lot of duplicates. I need to get the record "id" only when all the columns are matched
If you want the original rows that are duplicated on the specified columns, then you can use window functions:
select t.*
from (select t.*,
count(*) over (partition by candidateid, bgvtype, DepartmentId, BUId, CustomerId, ProjectId) as cnt
from table1 t
where status in (1,0)
) t
where cnt >= 2;
I have a table where storing details
ID NAME
1 A
2 A
1 A
I need the output like
ID Name Count
1,2 A 3
Please help to get the output like that in oracle select query
In Oracle, you can use listagg(), but it has no distinct option. So, use a subquery and two levels of aggregation:
select listagg(id, ',') within group (order by id) as id, name, sum(cnt)
from (select id, name, count(*) as cnt
from t
group by id, name
) x
group by name;
I have a PostgreSQL database table called "user_links" which currently allows the following duplicate fields:
year, user_id, sid, cid
The unique constraint is currently the first field called "id", however I am now looking to add a constraint to make sure the year, user_id, sid and cid are all unique but I cannot apply the constraint because duplicate values already exist which violate this constraint.
Is there a way to find all duplicates?
The basic idea will be using a nested query with count aggregation:
select * from yourTable ou
where (select count(*) from yourTable inr
where inr.sid = ou.sid) > 1
You can adjust the where clause in the inner query to narrow the search.
There is another good solution for that mentioned in the comments, (but not everyone reads them):
select Column1, Column2, count(*)
from yourTable
group by Column1, Column2
HAVING count(*) > 1
Or shorter:
SELECT (yourTable.*)::text, count(*)
FROM yourTable
GROUP BY yourTable.*
HAVING count(*) > 1
From "Find duplicate rows with PostgreSQL" here's smart solution:
select * from (
SELECT id,
ROW_NUMBER() OVER(PARTITION BY column1, column2 ORDER BY id asc) AS Row
FROM tbl
) dups
where
dups.Row > 1
In order to make it easier I assume that you wish to apply a unique constraint only for column year and the primary key is a column named id.
In order to find duplicate values you should run,
SELECT year, COUNT(id)
FROM YOUR_TABLE
GROUP BY year
HAVING COUNT(id) > 1
ORDER BY COUNT(id);
Using the sql statement above you get a table which contains all the duplicate years in your table. In order to delete all the duplicates except of the the latest duplicate entry you should use the above sql statement.
DELETE
FROM YOUR_TABLE A USING YOUR_TABLE_AGAIN B
WHERE A.year=B.year AND A.id<B.id;
You can join to the same table on the fields that would be duplicated and then anti-join on the id field. Select the id field from the first table alias (tn1) and then use the array_agg function on the id field of the second table alias. Finally, for the array_agg function to work properly, you will group the results by the tn1.id field. This will produce a result set that contains the the id of a record and an array of all the id's that fit the join conditions.
select tn1.id,
array_agg(tn2.id) as duplicate_entries,
from table_name tn1 join table_name tn2 on
tn1.year = tn2.year
and tn1.sid = tn2.sid
and tn1.user_id = tn2.user_id
and tn1.cid = tn2.cid
and tn1.id <> tn2.id
group by tn1.id;
Obviously, id's that will be in the duplicate_entries array for one id, will also have their own entries in the result set. You will have to use this result set to decide which id you want to become the source of 'truth.' The one record that shouldn't get deleted. Maybe you could do something like this:
with dupe_set as (
select tn1.id,
array_agg(tn2.id) as duplicate_entries,
from table_name tn1 join table_name tn2 on
tn1.year = tn2.year
and tn1.sid = tn2.sid
and tn1.user_id = tn2.user_id
and tn1.cid = tn2.cid
and tn1.id <> tn2.id
group by tn1.id
order by tn1.id asc)
select ds.id from dupe_set ds where not exists
(select de from unnest(ds.duplicate_entries) as de where de < ds.id)
Selects the lowest number ID's that have duplicates (assuming the ID is increasing int PK). These would be the ID's that you would keep around.
Inspired by Sandro Wiggers, I did something similiar to
WITH ordered AS (
SELECT id,year, user_id, sid, cid,
rank() OVER (PARTITION BY year, user_id, sid, cid ORDER BY id) AS rnk
FROM user_links
),
to_delete AS (
SELECT id
FROM ordered
WHERE rnk > 1
)
DELETE
FROM user_links
USING to_delete
WHERE user_link.id = to_delete.id;
If you want to test it, change it slightly:
WITH ordered AS (
SELECT id,year, user_id, sid, cid,
rank() OVER (PARTITION BY year, user_id, sid, cid ORDER BY id) AS rnk
FROM user_links
),
to_delete AS (
SELECT id,year,user_id,sid, cid
FROM ordered
WHERE rnk > 1
)
SELECT * FROM to_delete;
This will give an overview of what is going to be deleted (there is no problem to keep year,user_id,sid,cid in the to_delete query when running the deletion, but then they are not needed)
In your case, because of the constraint you need to delete the duplicated records.
Find the duplicated rows
Organize them by created_at date - in this case I'm keeping the oldest
Delete the records with USING to filter the right rows
WITH duplicated AS (
SELECT id,
count(*)
FROM products
GROUP BY id
HAVING count(*) > 1),
ordered AS (
SELECT p.id,
created_at,
rank() OVER (partition BY p.id ORDER BY p.created_at) AS rnk
FROM products o
JOIN duplicated d ON d.id = p.id ),
products_to_delete AS (
SELECT id,
created_at
FROM ordered
WHERE rnk = 2
)
DELETE
FROM products
USING products_to_delete
WHERE products.id = products_to_delete.id
AND products.created_at = products_to_delete.created_at;
Following SQL syntax provides better performance while checking for duplicate rows.
SELECT id, count(id)
FROM table1
GROUP BY id
HAVING count(id) > 1
begin;
create table user_links(id serial,year bigint, user_id bigint, sid bigint, cid bigint);
insert into user_links(year, user_id, sid, cid) values (null,null,null,null),
(null,null,null,null), (null,null,null,null),
(1,2,3,4), (1,2,3,4),
(1,2,3,4),(1,1,3,8),
(1,1,3,9),
(1,null,null,null),(1,null,null,null);
commit;
set operation with distinct and except.
(select id, year, user_id, sid, cid from user_links order by 1)
except
select distinct on (year, user_id, sid, cid) id, year, user_id, sid, cid
from user_links order by 1;
except all also works. Since id serial make all rows unique.
(select id, year, user_id, sid, cid from user_links order by 1)
except all
select distinct on (year, user_id, sid, cid)
id, year, user_id, sid, cid from user_links order by 1;
So far works nulls and non-nulls.
delete:
with a as(
(select id, year, user_id, sid, cid from user_links order by 1)
except all
select distinct on (year, user_id, sid, cid)
id, year, user_id, sid, cid from user_links order by 1)
delete from user_links using a where user_links.id = a.id returning *;
I'm working with Sql server 2008.i have a table contains following columns,
Id,
Name,
Date
this table contains more than one record for same id.i want to get distinct id having maximum date.how can i write sql query for this?
Use the ROW_NUMBER() function and PARTITION BY clause. Something like this:
SELECT Id, Name, Date FROM (
SELECT *, ROW_NUMBER() OVER (PARTITION BY Id ORDER BY Date desc) AS ROWNUM
FROM [MyTable]
) x WHERE ROWNUM = 1
If you need only ID column and other columns are NOT required, then you don't need to go with ROW_NUMBER or MAX or anything else. You just do a Group By over ID column, because whatever the maximum date is you will get same ID.
SELECT ID FROM table GROUP BY ID
--OR
SELECT DISTINCT ID FROM table
If you need ID and Date columns with maximum date, then simply do a Group By on ID column and select the Max Date.
SELECT ID, Max(Date) AS Date
FROM table
GROUP BY ID
If you need all the columns but 1 line having Max. date then you can go with ROW_NUMBER or MAX as mentioned in other answers.
SELECT *
FROM table AS M
WHERE Exists(
SELECT 1
FROM table
WHERE ID = M.ID
HAVING M.Date = Max(Date)
)
One way, using ROW_NUMBER:
With CTE As
(
SELECT Id, Name, Date, Rn = Row_Number() Over (Partition By Id
Order By Date DESC)
FROM dbo.TableName
)
SELECT Id --, Name, Date
FROM CTE
WHERE Rn = 1
If multiple max-dates are possible and you want all you could use DENSE_RANK instead.
Here's an overview of sql-server's ranking function: http://technet.microsoft.com/en-us/library/ms189798.aspx
By the way, CTE is a common-table-expression which is similar to a named sub-query. I'm using it to be able to filter by the row_number. This approach allows to select all columns if you want.
select Max(Date) as "Max Date"
from table
group by Id
order by Id
Try with Max(Date) and GROUP BY the other two columns (the ones with repeating data)..
SELECT ID, Max(Date) as date, Name
FROM YourTable
GROUP BY ID, Name
You may try with this
DECLARE #T TABLE(ID INT, NAME VARCHAR(50),DATE DATETIME)
INSERT INTO #T VALUES(1,'A','2014-04-20'),(1,'A','2014-04-28')
,(2,'A2','2014-04-22'),(2,'A2','2014-04-24')
,(3,'A3','2014-04-20'),(3,'A3','2014-04-28')
,(4,'A4','2014-04-28'),(4,'A4','2014-04-28')
,(5,'A5','2014-04-28'),(5,'A5','2014-04-28')
SELECT T.ID FROM #T T
WHERE T.DATE=(SELECT MAX(A.DATE)
FROM #T A
WHERE A.ID=T.ID
GROUP BY A.ID )
GROUP BY T.ID
select id, max(date) from NameOfYourTable group by id;
Let's say I have a table with two columns, one column for the ID and another for a Name. All the names in this table appear more than once.
How can I get all the IDs in the table excluding the smallest IDs for each Name?
In SQL Server 2005+ you could go like this:
SELECT ID FROM atable
EXCEPT
SELECT MIN(ID) FROM atable GROUP BY Name
I would use a CTE (Common Table Expression) using the ROW_NUMBER() ranking function for that:
;WITH GroupedNames AS
(
SELECT ID, Name,
ROW_NUMBER() OVER(PARTITION BY Name ORDER BY ID) AS 'RowNum'
FROM
dbo.YourTable
)
SELECT *
FROM GroupedNames
This will "partition" your data by means, e.g. create groups by name, and each group will get consecutive numbers starting at 1. This way, you can easily select everything except the entry (ID, Name) with the smallest ID with this:
.....
SELECT *
FROM GroupedNames
WHERE RowNum > 1
and if you need to, you can even use this construct to actually delete all those names with a row number bigger than 1 (all the "duplicates"):
;WITH GroupedNames AS
(
SELECT ID, Name,
ROW_NUMBER() OVER(PARTITION BY Name ORDER BY ID) AS 'RowNum'
FROM
dbo.YourTable
)
DELETE FROM GroupedNames
WHERE RowNum > 1
Maybe this would work?
SELECT id FROM table WHERE id NOT IN (SELECT MIN(id) FROM table GROUP BY name)
SELECT DISTINCT b.id
FROM yourTable a
JOIN yourTable b
ON a.name = b.name
AND a.id < b.id