duplicate annihilator

Seven examples of the uniq command: The uniq command in Linux can be used to process repeated lines in text files, this tutorial explains some of the most common usage of the uniq command, which may be helpful to you. The following file test will be used as a test file to explain how the uniq command works. $ Cat testaaaabbbbbbxx1. Syntax: $ uniq [-options] When the uniq command does not add any parameters, it will only remove duplicate rows and print

During normal work, you may encounter a system prompt ORA-01452 when you try to create a unique index for one or more columns in the database table: you cannot create a unique index and duplicate records are found. The following describes several methods for searching and deleting duplicate records (using the table CZ as an example ):The structure of the table CZ is as follows:SQL> desc czName Null? Type---

We may often encounter such an error during our code writing:[OBJC]View Plaincopy print? "Font-size:32px;color: #ff0000;" >LD: 4 Duplicate symbols for architecture x86_64 Clang: error:linker command failed with exit code 1 (use-v to see invocation) Read the cause of the error carefully to find a few key words: "duplicate" and "symbols". The Chinese meaning of

As the time of the system grows, the files in the system will become more and more, sometimes we in the day-to-day operation of the file, will continue to copy and paste the relevant files, resulting in the system Explorer has a lot of duplicate files, these files greatly occupy the hard disk space, we can find them through the software and delete. Method/Step We can use the Rubik's cube to optimize a large number of clean-up functions to achieve th

. Fortunately, MySQL takes this into account, providing the syntax that, when an insert is made insert … on duplicate key update , if the insert data causes a unique index (including the primary key index) to conflict, that is, if the unique value is duplicated, the insert operation is not performed and the subsequent update operation is performed.For example, there is now a table test,test table with field A, a primary key or a unique index on a

As an Oracle Database developer or DBA, you often experience the problem of trying to create a unique index on a column or column in a library table, prompting ORA-01452: You cannot create a unique index and find duplicate records. Here we take table code_ref as an example to discuss this problem and its solution. Error is on line 1th: ORA-01452: Unable to CREATE UNIQUE INDEX; Find duplicate keyword Ora

Tags: mybatis sql removal duplicate keep one recordThere are two meanings of duplicate records, one is a completely duplicate record, that is, all fields are duplicated records, and the second is some key field duplicate records, such as the Name field repeats, and other fields may not be repeated or can be ignored.1,

RMAN duplicate upgrades the versions of databases in the production environment or tests the performance and impact of new applications, backup and recovery, etc, we can clone it from the production environment to the local without affecting the normal use of the production database. We can use the rman duplicate Method and Its simple method to implement this function. The

Mysql-redundancy and duplicate indexes, mysql-redundant Indexes Mysql allows you to create multiple indexes on the same column, whether intentionally or unintentionally. mysql needs to maintain duplicate indexes separately, and the optimizer also needs to consider the query optimization individually, this affects performance. Duplicate indexes refer to the same t

This article describes how to insert duplicate values in the unique column in mysql. it is mainly based on the mysql platform. through these solutions, you can implement some new functions and applications. This article will be shared here with developers. When unique columns on a UNIQUE key to insert records containing duplicate values, we can control how MySQL handles this situation: use the IGNORE keywor

There are many ways to delete duplicate records. Here I summarize a variety of SQL statements for deleting restart records, such as deleting duplicate id data and searching for duplicate records, remove the smallest record, delete the repeat record, retain only one record and delete the redundant record in the table. The repeat record is determined based on a sin

The deduplication technology can provide a larger backup capacity, ensure data retention for a longer period of time, and achieve continuous verification of backup data, improve the level of data recovery service, and facilitate the implementation The deduplication technology can provide a larger backup capacity, ensure data retention for a longer period of time, and achieve continuous verification of backup data, improve the level of data recovery service, and facilitate the implementation D

Php deletes duplicate rows in a text file. Php: How to delete duplicate rows in a text file this article describes how to delete duplicate rows in a text file in php. I would like to share with you how to delete repeated rows in text files in php. 　Php deletes duplicate rows in a text file This example describes how

Select * from zxzx t where id in (select max (id) from zxzx t1 group by t1.type) order by id desc The above example is filtered by type. The following is an excerpt from the Internet: I. Filtering duplicate data 1. Completely Repeated Records /* Function: the specified field is completely repeated */Select distinct field 1, Field 2, Field 3 from data table2. Record with duplicate key fields /* Data Structur

SQL statement for querying and deleting duplicate records From: distinct (peopleid) to judgeSelect * from peopleWhere peopleid in (select peopleid from people group by peopleid having count (peopleid)> 1)2. Delete unnecessary duplicate records in the Table. Repeat records are determined based on a single field (eagleid), leaving only the records with the smallest rowidDel

Oracle uses rowid to delete duplicate records in a table First look at the table myemp Identify records with duplicate data Identify records with no duplicate data Identify non-Repeated Records Or Select * From myemp e where rowid = (select max (rowid) from myemp E2 where E. userid = e2.userid and E. Username = e2.username and E. Salary = e2.salary)

After migrating the data of a test system from Oracle 10 Gb to 11 GB, I heard the developers say that they failed to execute an SQL statement to create an index, but it can be executed normally in 10 Gb. This index is a function index with duplicate columns. It may be incorrect and this index is not useful. Therefore, you have never paid attention to this index. I felt quite interesting, so I tried it myself: 1. First, let's look at the 11g situation:

1. -- query the duplicate value of a column (or multiple columns) (only the value of the duplicate record can be found, not the information of the entire record) -- For example, query records with repeated item_no and item_subno Select item_no, item_subnofrom stuinfo Group by item_no, item_subno Having (count (*)> 1 2. -- query records with duplicate value

How to quickly delete duplicate records in SQL Server Developer nightmare-delete Repeated Records Presumably, every developer has had a similar experience. When querying or collecting statistics on the database, the query and statistics results may be inaccurate due to repeated records in the table. The solution to this problem is to delete these duplicate records and keep only one of them. In SQL S

[on DUPLICATE KEY update in the arena] If the table is not insert, if so, update will need to use the MySQL on DUPLICATE KEY update syntax, so you can write less if statements in the code to judge the The on DUPLICATE KEY update is specified at the end of the INSERT statement, and when the row is inserted causes a d