duplicate annihilator

Tags: cannot ima operation basis useful EXP GROUP by created fullyReasonIn the process of operating the database, we may encounter this situation, the data in the table may be repeated, so that we have a lot of difficulties in the operation of the database, so how to delete these duplicate data? You may encounter a job when you try to create a unique index on a column or column in a library table, you are prompted to ORA-01452: You cannot create a uni

Tags: using SP data BS as nbsp database learning BRDuplicate data can have two cases, the first: only some fields in the table, the second: Two rows of records are identical.First, the deletion of duplicate data for partial fieldsLet's start by talking about how to query for duplicate data.The following statements can query for duplicates of those data:Select field 1, Field 2,count (*) from table name Group

Introduction: Oracle DatabaseThe operation is a complex process. Pay special attention to the details during the operation. For example, we may encounter this situation during the operation of the Oracle database, and the data in the table may be repeated, this makes database operations inconvenient. How can we delete the useless data? The deduplication technology can provide a larger backup capacity for longer data retention, continuous verification of backup data, improve the level of data rec

1. delete completely Repeated Records Completely duplicated data is usually caused by the absence of primary key/unique key constraints.Test data: Copy codeThe Code is as follows: if OBJECT_ID ('duplicate _ all') is not null Drop table duplicate_all GO Create table duplicate_all ( C1 int, C2 int, C3 varchar (100) ) GO Insert into duplicate_all Select 1,100, 'aaa' union all Select 1,100, 'aaa' union all Select 1,100, 'aaa' union all Select 1,100, 'aaa'

Replace syntax The syntax format for replace is: 1. Replace into table_name (col_name, ...) VALUES (...) 2. Replace into table_name (col_name, ...) Select ... 3. Replace into table_name set Col_name=value, ... Algorithm Description: The run of replace is similar to insert, but if the old record has the same value as the new record, the old record is deleted before the new record is inserted, namely: 1. Try inserting the new row into the table 2. When an insert fails because of a

When you use Excel tables to block large quantities of data, you will inevitably find some duplicate rows and duplicate data, then we should delete those duplicate data, so as not to affect our work, in Excel to delete duplicate data and duplicate rows in the way there are m

There can is types of duplication of rows in a table1. Entire row getting duplicated because there is no primary key or unique key.2. Only primary key or unique key value is different and remaining all values are same.Scenario 1:delete duplicate rows without primary key or unique key.Let us create the following example.CREATE TABLE Customers1 (CustId Int, CustName varchar (), custcity varchar (), passport_number varchar) goInsert into Customers1 Value

In the previous blog, we used the duplicate method to create a physical standbyblog. csdn. netaaron8219articledetails38434579. Today we are talking about some problems encountered when using the non-duplicate method to create a slave database in 11g. In 10 Gb, the following methods can be used to create the backup Database Control File RMANbackup In the previous blog, I used the

1. delete completely Repeated Records Completely duplicated data is usually caused by the absence of primary key/unique key constraints.Test data:Copy codeThe Code is as follows:If OBJECT_ID ('duplicate _ all') is not nullDrop table duplicate_allGOCreate table duplicate_all(C1 int,C2 int,C3 varchar (100))GOInsert into duplicate_allSelect 1,100, 'aaa' union allSelect 1,100, 'aaa' union allSelect 1,100, 'aaa' union allSelect 1,100, 'aaa' union allSelect

Search for records with all repeated titles: SELECT * FROM t_info a WHERE ((SELECT COUNT(*) FROM t_info WHERE Title = a.Title) > 1) ORDER BY Title DESC 1. Search for duplicate records 1. Search for all Repeated Records Select * From table Where repeated field In (Select repeated field From Table Group By repeated field Having Count (*)> 1) 2. Filter duplicate records (only one record is displayed) Select

MySQL: on duplicate key update usage, mysqlduplicateYou can use this syntax to determine whether a record exists when inserting a record. If the record does not exist, insert the record. Otherwise, the record is updated, which is convenient and requires no execution of two SQL statements.This statement is in mysql, but not in standard SQL statements.Insert into .. on duplicate key to update multiple rowsIf

How to query and delete duplicate records(1)1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (peopleid ).Select * from peopleWhere peopleid in (select peopleid from people group by peopleid having count (peopleid)> 1)2. Delete unnecessary duplicate records