The Duplication tag covers the topic of duplicated data and the strategies involved in removing the duplicates, often referred to as deduplication or simply dedupe.

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1answer
41k views

Optimal way to ignore duplicate inserts? [duplicate]

Background This problem relates to ignoring duplicate inserts using PostgreSQL 9.2 or greater. The reason I ask is because of this code: -- Ignores duplicates. INSERT INTO db_table (...
4
votes
2answers
8k views

How do I remove duplicate records in a join table in PostgreSQL?

I have a table that has a schema like this: create_table "questions_tags", :id => false, :force => true do |t| t.integer "question_id" t.integer "tag_id" end ...
4
votes
2answers
1k views

How do I delete unique rows from a table with duplicate keys?

I have the following data: road | ID | other column | other column | ------------------+------+---------------+--------------+ MAIN ST | 1 | ... | ...
2
votes
2answers
6k views

remove duplicate rows in mysql table that does not contain primary key

I have a table item having just one column name:- name ----- toys shirt mobile Shirt speaker Toys .... .... I am trying to delete duplicate rows except one duplicated record with the help of below ...
9
votes
3answers
69k views

select rows where column contains same data in more than one record

I have a table that has a column called article_title. Let's say the table name is articles. I need to find out the records where the article_title data is the same on more than one record. Here's ...
10
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5answers
12k views

How do I copy my SQL Azure database to a local SQL Server instance?

I have an OLTP database hosted on a SQL Azure instance. I want to pull a copy of the database down from the cloud so I can run some heavy extracts and OLAP-style queries against it without impacting ...
1
vote
1answer
2k views

Duplicate entry in MySQL slave

I have a MySQL master-slave replication setup. When I checked show slave status, I got the result as Slave_Sql_running:No and last error as Duplicate entry 'x' on query. But when I tried to delete ...
2
votes
1answer
39 views

Should I create many ID for a same Person/entity in my DB?

In my model, I must store the name of the teacher of some kids and the classroom in which the teachers work, let’s say. All of the hundreds of teachers in the schools have 1 and only 1 classroom, ...