In the database structured query language (SQL), the DELETE statement removes one or more records from a table.

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Why is truncate DDL?

I have an interview question, which being asked during my interview. I answered the question, but interviewer was not convinced with my answer. So, please let me know the what would be the correct ...
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30 views

I have a table from which I can retrieve information but I cannot update or delete information

I can update and delete items via PhpMyAdmin. I changed the owner to mysql. My program is a clone of insert, update, and delete that is functioning for other tables within the database. I receive a ...
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2answers
42 views

How many records should be deleted when batch delete is used?

I am going to migrate a large amount of data from one table to other table. The target data source table has foreign key constrains, so I am not able to use DELETE with OUTPUT clause, but need to have ...
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1answer
61 views

How is it possible that two deletes give a deadlock, if they do have different primary key data

I am getting a deadlock by the same delete stored procedures that is called by two different threads for deleting two concurrent records. The deadlock happened on the primary key index of the X ...
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1answer
230 views

DELETE from Linked Server table using OPENQUERY and dynamic criteria

I'm attempting to run a DELETE statement from my local MSSQL Server to delete appropriate records from a table in my remote linked server using OPENQUERY(). I'm using the following code, but it seems ...
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1answer
45 views

SQL Server Deadlock on delete

I have a query like this: with xx as ( SELECT [FilePath], ROW_NUMBER() over (partition by [FilePath] order by [FilePath]) as RowNumber FROM [dbo].[foo] ...
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40 views

speed up ghost cleanup

In SQL Server I have a table that is filled often and also gets deleted often. Because several threads write and erase data from that table I cannot even truncate it because there is always someone ...
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1answer
69 views

Delete files from disk, with a job, respecting some rules ( SQL Server 2008 )

We have An application that our customers use to download and upload files. I need to delete these files from disk after 30 days, of if it was downloded, in 7 days. How can i Use the script below, ...
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2answers
118 views

PostgreSQL : dependencies on a schema

I need to delete a schema in my PostgreSQL database. I would like to make sure that the schema is not used in another schema (for instance : this schema is used for a view in another one). Is there a ...
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0answers
12 views

How to do updates on all rows at every button click [migrated]

I have a python app that has an admin dashboard. There I have a button called "Update DB". (The app uses MySQL and SQLAlchemy) Once it's clicked it makes an API call and gets a list of data and ...
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12 views

Releasing space after deleting datafiles

I'm deleting old backup tablespaces with option using contents and datafiles in TOAD. Datafiles were deleted, but no space was released: Filesystem GB blocks Free %Used Iused %Iused ...
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0answers
16 views

Access 2010 delete and append queries run partially then give “Read Only” error

I have a number of append and delete queries written in Access 2010 that link to and modify tables on our SharePoint 2010 site. These queries have run without problem for months, but suddenly they've ...
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0answers
43 views

Purging Data that has Foreign Keys

I have a transaction database that we recently went live with. The number of rows in the tables are starting to climb into the millions. So I am looking at how to purge the older data. I have written ...
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1answer
24 views

DELETE statement execution cancellation in SSMS

I ran a delete statement with wrong WHERE condition (which deletes all records from table instead of just 10 records) but during execution I found it and CANCELLED the execution in sql server ...
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1answer
38 views

Delete Duplicates Leaving One of Two Identical Records [closed]

Delete Duplicates Leaving One of Two Identical Records One of my MySQL database tables contains four BLObs in each row. When it was first set up the table had no keys. However when I now try to add a ...
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0answers
30 views

MySQL 5.1.73-cll and engine MyISAM PRO AND CONS FOR THE FOLLOWING 2 'DELETE' APPROACHES [closed]

For MySQL 5.1.73-cll and engine MyISAM what are the pros and cons for the following two possibilities of 'deleting' rows(let's say that a user want's to delete his profile/delete some of his products ...
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1answer
51 views

MySQL Deadlock - accessing different primary key values also creating deadlock

I went through MySQL logs and found the reason for deadlock 1st thread is trying to execute below query. Which is waiting for thread 2. UPDATE M_SAMP SET MM_Q_IND=0 WHERE M_ID IN (SELECT M_ID FROM ...
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0answers
24 views

How to find Deleted and Updated record tables in MYSQL database?

I have scenario like below. I need to find Deleted records and updated records effected tables in mysql. Ex: I update my Name or Email Id in UI that is effected in some tables either one table or ...
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2answers
2k views

Fastest way to delete matching rows in MySQL?

I have more than 10 million records in a table. I want to delete the records where the email column contains .ac.. What is the fastest method to perform the task? Table Schema CREATE TABLE `master` ...
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47 views

Delete the second record where a user has two records

I have a simple database scheme, which due to previously being badly set up has numerous duplicate records. record_table |--------------------------------------------------------| | id | subid | ...
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1answer
20 views

Run SQL requests generated by some script

I'm using this script to delete data from all the tables in my database. It generates DELETE statements in proper order, each request in one row : DECLARE @schema_name sysname; DECLARE @table_name ...
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6answers
4k views

DELETE command not completing on 30,000,000 row table

I have inherited a database and am looking to clean and speed it up. I have a table that contains 30,000,000 rows, many of which are junk data made by an error by our programmer. Before I add any new, ...
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2answers
113 views

DELETE seems to hang

The following command: DELETE FROM hours WHERE id IN (SELECT id FROM holdkey WHERE persons_id=60) seems to hang indefinitely. However, the corresponding SELECT * command completes in a fraction of ...
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3answers
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Do I need to reindex mysql table after bulk delete?

I have a table in MySQL with a lot of INSERT and SELECT at every second. And there is a bulk delete of some older data once in a day. Do I need to reindex the table after delete? I want to increase ...
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0answers
62 views

delete millions of rows from multiple tables

Hi we have to delete between 40 and 55% of records from several tables that have between 40 million and 100 million rows. Is it better to copy the rows we want to keep to a new table, drop the source ...
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1answer
242 views

Remove all records with duplicates in db2. (Not just the duplicate records)

How can I remove all the records with duplicates in db2. I have looked at various answers but they only remove the duplicates leaving one record from that set in the table. This is what I found ...
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1answer
81 views

Full table scan - high water mark

When doing a full-table scan, why does Oracle scan all the rows beneath the high-water mark? Doesn't it know that some of the rows have been deleted and that they shouldn't be scanned?
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1answer
56 views

decrement all columns entry when row is deleted

I have a column in a table containing the row_number, some kind of id number to identify the row. When I delete one row, I need the other rows to have their row_number decremented, to keep them ...
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2answers
229 views

Why doesn't a delete increase unused space in a table?

If I populate the following table: IF OBJECT_ID ('dbo.CleanTableTest', 'U') IS NOT NULL DROP TABLE dbo.CleanTableTest; GO CREATE TABLE dbo.CleanTableTest (FileName nvarchar(4000), ...
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1answer
49 views

DELETE from OPENQUERY alias not working

I'm trying to use the following code to execute a DELETE statement on a linked server. I'm trying to delete all records from the remote server where there is a match on a certain ID field in both the ...
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6answers
29k views

Best way to delete very large recordset in Oracle

I manage an application which has a very large (nearly 1TB of data with more than 500 million rows in one table) Oracle database back end. The database doesn't really do anything (no SProcs, no ...
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2answers
84 views

Deleting rows from a table with a very small amount of expansion space

I have multiple tables that I have backed up the data in, and now am deleting the old data for the time, archiving is not an option due to space constraints at this time. I have tried running the ...
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3answers
240 views

Bulk Delete for Large Table in MySQL

I have a Notification table contains about 100 million rows host in Amazon RDS with 1000 IOPS, and I want to delete those rows older than one month. If I do DELETE FROM NOTIFICATION WHERE CreatedAt ...
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38 views

Update on table deletes the record

I'm having a problem in my oracle database, I have a table PAYMENTS which has an ID (PK) and when I want to update a record: UPDATE PAYMENTS SET AMOUNT = 2000 WHERE ID = '1'; The record with ID = ...
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1answer
71 views

Delete from table where two of the three keys in another select

I have tableA which has 4 columns: IDA (bigint), IDB (int), IDC (varchar(255)) and comment (varchar(255)). The primary key is (IDA, IDB, IDC). I'm required to delete the records where the count of ...
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3answers
242 views

Deleting data from a large table with replication

I need to delete all the rows from a given table. The table contains millions or records. The master database is being replicated to several slaves and I wish to do that without creating a replication ...
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4answers
510 views

MySQL: Keep the 10 most recent rows for each user

I have a table saving scores for a game that have 3 columns (more in practice, but it is easier for everyone this way): userid : the id of the user that got the score timestamp: the time the score ...
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0answers
108 views

insert record to child table which doesn't map to parent table - possible?

Actually I've 2 relevant questions: insert record to child table which doesn't map to parent table - possible? ON DELETE NO ACTION - when a record in parent table is deleted, it should affect ...
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1answer
61 views

SELECT count vs DELETE JOIN. Why/how are they different?

Can someone explain in what way these queries could be different and the results are not the same? > begin; Query OK, 0 rows affected (0.01 sec) >select count(*) from tableA a JOIN tableB ...
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1answer
59 views

Unable to delete a record in Mysql

Let's say I have table name Company with two columns cname, location. In the table I am having two records with cname |location Asmetric |Dallas Sophore |Washington on this table when I ...
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1answer
28 views

Can having a LIMIT on DELETE degrade performance dramatically?

I have a database project in php and mysql. For, hopefully redundant, data security I added a LIMIT 1 to the delete($uniqueID) php function we use. Nobody cared because records really aren't ...
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1answer
112 views

Delete rows while updating references

Suppose I have a person table with an id and some other columns. Other tables reference the person table using ON UPDATE CASCADE. for instance: CREATE TABLE person (id int PRIMARY KEY); CREATE TABLE ...
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14 views

Lower resolution of record on MySQL

The database I'm currently working on logs about 50 columns of data per second on our plant. The current high frequency logging is due to ongoing test. However, going long term, this would not be ...
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42 views

Low batch Batchrequests/sec

I am running this query to do massive deletion in my database. I am looking at Batchrequests/sec and it is quite low (like 15% of what my server can handle) Is there any way to rewrite this query to ...
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0answers
43 views

Update existing (old) rows vs delete and insert when needed

I'm building a database system that needs to store login tokens for a system that validates if a users login token is valid or outdated. The table is pretty simple UserID int Primary Key LoginToken ...
0
votes
3answers
154 views

Delete all the data from all tables

I have a little problem. I have to delete all the data from our database. I don't want to drop tables, only delete the data sets. These are 47 tables in total. I tried the following: Delete ...
3
votes
1answer
377 views

Copy database and clear down data (including linked tables) older than N days

I have a sizable production database (140GB) on MS SQL Server 2012, which I'm trying to automatically download to our development environments on a periodical basis (every week or on demand). I'm not ...
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3answers
150 views

Slow DELETE in MySQL with a subquery

I am running the following DELETE SQL on a MySQL database on a MyISAM/utf8 table. The SQL is called in a loop, once time per Users (in this case):- DELETE FROM regulatory WHERE documentid IN ( ...
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1answer
827 views

Deleting Record from Linked Table Slow in MS Access

I have a Microsoft Access database that is linked to a SQL Server 2000 backend. It has one form with several subforms, all using information from linked tables. When I try to delete a record from one ...
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1answer
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ON DELETE CASCADE pseudo delete

For data integrity ON DELETE CASCADE is necessary but it's really dangerous when a delete affects like a Chain Reaction! I know one way to prevent this is to make a pseudo delete by putting a ...