How to delete duplicate records

Suppose I have a table with N columns and K TAB (K < N) for which I should not have duplicated (in other words, the K column can be a key primary candidated)
Can you give me a SQL query to delete duplicate records of TAB for columns K?
Thank you very much!

remove the tab where rowid not in (select min (rowid) of the TAB group by k)

Tags: Database

Similar Questions

Delete duplicate records

Dear all,
How to remove duplicates of records in table. Can you tell me the writing of the application.
For example:
Col1 Col2 COL3
1 2 3
1 2 4
2 2 2
2 2 2
5 5 5
5 5 5
1 2 3
I need under the outlet.
Col1 Col2 COL3
1 2 3
1 2 4
2 2 2
5 5 5
Thank you.

To do this homework, you must use GROUP BY, COUNT function (assuming the analytical function is not yet covered in the course). Please try yourself and post the problem you are experiencing. Believe me, it is very important to your learning.

How to delete several records by selecting the check box

Hi I am a newbie in oracle forms Builder. I want to delete multiple records at the same time, when I click on the button. I have a 'emp_block' and 'control_block '.
emp_block information: -.
I have all the columns displayed in this block as empno, ename, sal, hiredate, deptno, comm.
Other than that I add a new item of type "checkbox" and his name is "checkbox".
control_block information: -.
I have a "push button" in this control block.
I added trigger "when-button-pressed" and write this line of code: -.
EXECUTE_TRIGGER("ON-DELETE");
COMMIT;
"DELETE" is a trigger of form level. In this trigger, I wrote this code: -.
BEGIN
DELETE FROM EMP WHERE EMPNO =: EMP_BLOCK. CHECKBOX;
END;
Problem: -.
Not one selected record is deleted when I click on the button Delete.
I want to check little matter how much and when I press on delete button it has deleted all records whose box has been checked.
Please help me...

Welcome to the forum.

In your WHEN-BUTTON-PRESS-trigger, just put your entire code and remove this EXECUTE_TRIGGER thing.

To remove all verified records within a block, you must loop through the block and delete each record, something like
```
BEGIN
  GO_BLOCK('YOUR_DATA_BLOCK');
  FIRST_RECORD;
  LOOP
    EXIT WHEN :SYSTEM.RECORD_STATUS='NEW';
    IF :YOUR_DATA_BLOCK.CHECKBOX='Y' THEN
      DELETE_RECORD;
    ELSE
      EXIT WHEN :SYSTEM.LAST_RECORD='TRUE';
      NEXT_RECORD;
    END IF;
  END LOOP;
END;
```
Make sure that you set the property "value when checked" section of box check "Y".

Col1	Col2	COL3
1	2	3
1	2	4
2	2	2
2	2	2
5	5	5
5	5	5
1	2	3

Col1	Col2	COL3
1	2	3
1	2	4
2	2	2
5	5	5

deleting duplicate records

I'm doing all the records in the small suitcase to eliminate the sensitivity of the data to display for example

(1) setting a day email set email = lower (email); who gives a unique constraint error

(2) I saw emails in duplicate with the following command
Select E-mail
enamel
where lower (email) in
(select lower (email)
enamel
Lower group (email)
view count (*) > 1) order by e-mail CSA;

(3) I want to delete duplicate entries as described in (2) with the sql statement because they are over 500 and if I start to remove manually it will take too much of my time

Thank you and best regards

SQL> create table t(email varchar2(100))
  2  /

Table created.

SQL> create unique index t_idx on t(email)
  2  /

Index created.

SQL> insert into t values('[email protected]')
  2  /

1 row created.

SQL> insert into t values('[email protected]')
  2  /

1 row created.

SQL> insert into t values('[email protected]')
  2  /

1 row created.

SQL> insert into t values('[email protected]')
  2  /

1 row created.

SQL> insert into t values('[email protected]')
  2  /

1 row created.

SQL> commit
  2  /

Commit complete.

SQL> select * from t
  2  /

EMAIL
----------------------------------------------------------------------------------------------------
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]

SQL> update t set email = lower(email)
  2  /
update t set email = lower(email)
*
ERROR at line 1:
ORA-00001: unique constraint (SYSADM.T_IDX) violated

SQL> delete
  2    from t
  3   where rowid not in (select rowid
  4                    from (select rowid,row_number() over(partition by lower(email) order by lower(email)) rno
  5                            from t)
  6                   where rno = 1)
  7  /

3 rows deleted.

SQL> update t set email = lower(email)
  2  /

2 rows updated.

SQL> select * from t
  2  /

EMAIL
----------------------------------------------------------------------------------------------------
[email protected]
[email protected]

SQL>

How to compare the content of two files so I can delete duplicate records

I'm trying to clean up several subfolders with duplicates without looking at the details of each record. Is it possible in Windows XP to compare the content of two files whether they are an exact replica.

Hi rav42010,

Follow the steps in the article.

Description of the tool in Windows XP disk cleanup

http://support.Microsoft.com/kb/310312

You can also use third-party app to perform the task using your favorite search engine.

Note: Using third-party software, including hardware drivers can cause serious problems that may prevent your computer from starting properly. Microsoft cannot guarantee that problems resulting from the use of third-party software can be solved. Software using third party is at your own risk.

How to delete the record from the classic report?

Hi all
I am currently working in the APEX 4.2.5.
I did a classic report and I want to click on the link 'delete' to remove the record.
But how can I do this?
Thanks in advance

See this recent thread on the forum: https://community.oracle.com/thread/3687421?start=0&tstart=0

Thank you

Tony Miller
Software LuvMuffin
Ruckersville, WILL

How to delete a record in the data store VMware

Hello
First VM4 & VM5 is migrated during the execution of the migration of the VM20, sort of migration of VM4 & VM5 failed a few minutes later. But VM4 folder could be seen under backup2 datastore. When VM4 is migrated again once finished VM20 migration, VM4_1 record can be seen in the data backup2 store. And VM4 folder includes a DB_backup - flat hard file.
So I have a few questions:
(1) how can I remove the VM4 because it's useless? Should I delete file DB_backup - flat hard and then delete the folder VM4? But I can't find measures to remove the VM4 folder in the store of data backup2. Who can provide the steps?
(2) how can I rename the folder VM4_1 to VM4 name?
Thank you!

Thanks Andre for clarification. Yes, even if the file can be renamed when the VM is turned on but this will lead to issues if we want to migrate the virtual computer to the another data store or if we stop & try to turn on. So please do not rename folder when the virtual machine is running.

Second approach will work fine. Renaming that is to display the name of the computer virtual, then SVMotion in another data store & and then you can bring the virtual machine to the previous data store.

Reference:VMware KB: rename a virtual machine and VMware ESXi and ESX records

How to delete duplicate AppData

I'm trying to set up my new 7 system. I have an SSD of 64Go with OS7 on that and a 500 GB HARD drive for data. I have been using the instructions in this link to move the folder of the mobile user to the SSD on the HARD drive. (http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/i-want-to-install-windows-7-on-a-solid-state-drive/7a72bda6-c37d-4b00-b99e-4b422dad62d4)

I got until I copied somehow the AppData in the SSD user Documents folder. Now I don't have a * vacuum * Documents folder. It is filled in double AppData.

How can I get My Documents folder clean and empty return once again (so I can move it) and get rid of the double AppData so I can continue to move the folders from the user on my D: drive? (I tried to just delete it in the trash but it hung the system)

Move the users folder is not supported by MS

You can redirect the libraries on another drive

Help with Discoverer Desktop, how to choose duplicate records
I use Discoverer 11g Desktop and am well want to ask for help.

I've created a report in the office, but I need the report to display only the records of people with more than 1 invoice for rental in the year.
Years old as a parameter. One of the columns of the report is person-id and there is a column called transaction_type that is filled with different types of transactions
the value of the transaction_type that I use for the report is "RENT_INVOICE", so I want that report to choose only
people infected with more than 1 'RENT_INVOICE' transaction_type records, leaving out records with only 1 'RENT_INVOICE '.
How can I do this in Discoverer Desktop or more? Help, please.
Hello
Well after having created the condition for the kind that you mentioned.
You must create a new calculation using the analytic function

It should be:
Count (transaction_type) more (personid partition)

This will give you the result to the num of records, now just add a new condition during this new element

Tamir

How to remove duplicate records...
Hello

I have a strange scenario below is the structure of the table

of km
Bangalore, Mumbai 100
Mumbai, Bangalore 100
Bangalore, Chennai 50

I want the output as given that the distance is even bangalore to Bombay and mumbai to bangalore I want only one instance...

of km
Bangalore, Mumbai 100
Bangalore, Chennai 50

I was able to find duplicate using following query records but put not able to come to the final...

Select a.frm, b.frm, a.km
distance a distance b
where a.frm = b.too
and b.frm = a.too

Thanks in advance...

Sree
```
WITH t AS (
            SELECT 'Bangalore' col1, 'Mumbai' col2, 100 col3 FROM DUAL
           UNION ALL
            SELECT 'Mumbai', 'Bangalore', 100 FROM DUAL
           UNION ALL
            SELECT 'Bangalore', 'Chennai', 50 FROM DUAL
          )
SELECT  DISTINCT LEAST(col1,col2) col1,
                 GREATEST(col1,col2) col1,
                 col3
  FROM  t
/

COL1      COL1            COL3
--------- --------- ----------
Bangalore Mumbai           100
Bangalore Chennai           50

SQL> 
```
SY.

ROW_NUMBER and duplicate records
Hello

Tried to delete duplicate records. The code below works, but would remove all, rather than simply the > #1 records:

(SELECT academic_period, load_week, sub_academic_period, person_uid, course_number,
course_reference_number, rowid that RID, row_number() over (partition of)
academic_period, load_week, sub_academic_period, person_uid, course_number,
order of course_reference_number of academic_period, load_week, sub_academic_period,
person_uid, course_number, course_reference_number)
Of THE cea
WHERE (academic_period, load_week, sub_academic_period, person_uid, course_number,)
IN course_reference_number)
(SELECT academic_period, load_week, sub_academic_period, person_uid, course_number,
course_reference_number
Of THE cea
GROUP of academic_period, load_week, sub_academic_period, person_uid, course_number,
course_reference_number
HAVING COUNT (*) > 1))

If I try to put 'rn' and rn > 1, I get ora-00933: Sql not correctly completed command

SELECT academic_period, load_week, sub_academic_period, person_uid, course_number,
course_reference_number, rowid that RID, row_number() over (partition of)
academic_period, load_week, sub_academic_period, person_uid, course_number,
order of course_reference_number of academic_period, load_week, sub_academic_period,
person_uid, course_number, course_reference_number): the nurse
Of THE cea
WHERE (academic_period, load_week, sub_academic_period, person_uid, course_number,)
IN course_reference_number)
(SELECT academic_period, load_week, sub_academic_period, person_uid, course_number,
course_reference_number
Of THE cea
GROUP of academic_period, load_week, sub_academic_period, person_uid, course_number,
course_reference_number
After HAVING COUNT (*) > 1)
and rn > 1

I tried to remove as"rn" and make "rn" and "rn", which gave me an error of syntax also. The '' rn > 1 and '' clause gets an error of syntax also. I gone through a bunch of different Web sites. All of this indicates the syntax I am using will work. However, any query I run into a TOAD, always error when I include the 'rn > 1.

Any ideas? Thank you!

Victoria
You mix two ways to identify duplicates.

One way is HAVING:
```
SELECT academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number
FROM cea
GROUP BY academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number
HAVING COUNT(*) > 1)
```
That tells you just what combinations of your group are more than once.

Another way is to analytical functions:
```
select *
from (
  SELECT academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number
         count(*) over (partition by academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number) cnt
  FROM cea
)
where cnt > 1
```
This will all return duplicate records - if some combinations has three duplicates, then this will return all three lines.

If you use the ROW_NUMBER() place COUNT() analytical analytical function, you get this:
```
select *
from (
  SELECT academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number
         row_number() over (partition by academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number) rn
  FROM cea
)
where rn > 1
```
All of these files without duplicates will get rn = 1. Those with duplicates gets rn = 1, rn = 2... If rn > 1 Gets all "unnecessary" records - the ones you want to remove.

If a deletion might look like:
```
delete cea
where rowid in (
  select rid
  from (
    SELECT ROWID as rid,
           row_number() over (partition by academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number) rn
    FROM cea
  )
  where rn > 1
)
```
Or if you want to manually inspect before you delete ;-):
```
select *
from cea
where rowid in (
  select rid
  from (
    SELECT ROWID as rid,
           row_number() over (partition by academic_period, load_week, sub_academic_period, person_uid, course_number, course_reference_number) rn
    FROM cea
  )
  where rn > 1
)
```
In another answer, you can find a way to remove duplicates with HAVING.
The point is that do you it either with or with ROW_NUMBER() - not both HAVING ;-)

Problem with deleting a record
I'm trying to figure out how to delete a record in a MySQL table using php on DWmx2004 server behaviors.
I have two pages: Page 1 (ck_insert.php) lists organizations of a field in the table. Next to each name is a "Delete" text link that leads to the Page 2 (ck_delete.php).

My link href page ck_delete.php ck_insert.php reads as follows:
< a href = "ck_delete.php? scrap = <?" PHP echo $row_rstSix ["ck_pk"];? > ">"
(ck_pk being the autoincremented in the MySQL table primary key field.)

On the second page, the selected organization appears in the expression "you want to remove (organisation_to_be_deleted) from the database?
Then I put in a box with the name of "gone" and the value Checked "gone".
Next is a button named 'Submit' tagged 'remove '.

The correct variable is transferred to the Page 2, but then when I click the button to delete the record deletion does not occur...

Please take a look at:
http://www.hopeless.me.UK/deleteimage.htm
where I posted the Page 2 image and images of the relevant DW completed dialog boxes.

The entries are clearly incorrect, because the system has not yet reached the goal of deleting a record and return the first page. I would be very grateful for help in sorting this point and tell me where I can find a clear explanation of how I'm supposed to take on this important task. So far what I've read left me confused, as you can see!
Thank you

Relax everyone. I've sorted it. I had to add a hidden field to the form.
Done and dusted.

How to delete records from a table that has a composite unique key duplicate
Hello
I get the customer data from various sources in the staging of the table where I insert in the database table where the combination of two columns is considered as a unique key. But there is a possibility of duplicates. How to find duplicates in a SQL or pl/sql

Thank you
Manoi.
Kassa,

You can see the duplicates by using the following query...
```
sql> select * from temp_rajesh;

      COL1       COL2 MESSAGE
---------- ---------- ------------------
       100        200 message
       100        200 message2
       300        400 message3
       400        500 message 4

sql> select col1, col2, count(*)
  2     from temp_rajesh
  3       group by col1, col2
  4         having count(*) > 1;

      COL1       COL2   COUNT(*)
---------- ---------- ----------
       100        200          2
```
-If in the case of duplicate records, you should see only the duplicates (according to some timestamp etc., you can use the functinon row_number analytic..)
```
  1  select col1, col2 from (
  2  select col1, col2,
  3         row_number() over (partition by col1, col2
  4                            order by message) rn
  5    from temp_rajesh)
  6*   where rn > 1
sql> /

      COL1       COL2
---------- ----------
       100        200
```
In the above example, I use message to order, you can replace it with activity_timestamp or the insertd_date according to your logic... when there are two records... one that you choose to duplicate.

Thank you
Rajesh.

Published by: Rajesh Chamarthi on November 20, 2009 12:05 AM (added for example)

How to avoid make records duplicate when you save a series?

How to avoid make records duplicate when you save a series?

When you schedule a recording for a TV series, Media Center automatically records episodes based on the options you set here.

1. click the Start button, click all programsand then click Windows Media Center.

2. on the Media Center start screen, navigate to tasks, click settings, click TV, click recorderand then click default record.

3 scroll to the series as the default record section.

4. do one of the following:

·         Under Show type, click the plus sign (+) or minus (-) button to record only new episodes, reruns or direct episodes.

·         Under channels, click the plus (+) or minus (-) record button present in this series on any channel, or on a specific channel.

·         According airtime, click the plus sign (+) or minus (-) button record shows in this series at any time, or only at a specific time.

·         Under the keep up to, choose how many records in this series to keep before older episodes are automatically deleted.

5. click on Save.

How to delete songs in Windows Media Player 11 duplicate?

How to delete songs in Windows Media Player 11 duplicate

Hello

Method 1:

I would recommend you to rebuild the database of Windows Media Player and see if the problem is resolved.

Here's how:
To resolve this problem, delete the Windows Media Player database. To do this, follow these steps:

1. exit Windows Media Player.

2. click on start, run, type %LOCALAPPDATA%\Microsoft\Media Player, and then click OK.

3. Select all the files in the folder and then click on Delete on the file menu.

Note: You don't have to remove the folders that are in this folder.

4. restart Windows Media Player.

Note: Windows Media Player automatically rebuilds the database.

Method 2:
If this does not resolve the problem, disable the Windows Media Player database cache files.

To do this, follow these steps:

1. exit Windows Media Player.

2. click on start, run, type % LOCALAPPDATA%\Microsoft, and then click OK.

3. Select the Media Player folder, and then click on Delete on the file menu.

4. restart Windows Media Player.

Method 3:

When you move digital media files on your computer, the file name and file path information remain unchanged in your library. Then when you select a file to play to its new location, a new entry is created in your library if you select the option automatically added to your library when played. As a result, your library can quickly contain a large number of entries, duplicate or invalid.

To prevent it be automatically added to your library of music files

1. in Windows Media Player, on the Tools menu, click Options.

2. on the Player tab, clear the files of music to add to the library when played check box.

Now, when you play music on your computer or the Internet, the file will not be added automatically to your library.

Method 4:

In the case where the duplicates are not removed:

There are also third-party applications to do the job. You can search your favorite search engine and download third-party software to remove the tracks in Windows Media Player 12 duplicate.

DISCLAIMER

Using third-party software, including hardware drivers can cause serious problems that may prevent your computer from starting properly. Microsoft cannot guarantee that problems resulting from the use of third-party software can be solved. Software using third party is at your own risk.

How to delete duplicate records

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