duplicate annihilator

Method One: Use in the programming of T-SQLAssign a column number, sort by col1,col2 combination, delete database duplicate rows (duplicate data), keep only one row//Col1,col2 is the database columnDelete a from (select Col1,col2,row_number () over (partition by col1,col2 ORDER by COL1) as RN from DATABASE) a where a.rn >1 method Two: Use in the ETL select distant into, this method with a new table, the non

Today in Bluediea see Taobao online recruitment, I believe the technology is still very cow Taobao, so hurriedly opened to see the topic and try to do. To the third problem card for a while, it is not do not come out, feel a very simple way but I can not think of a moment, but the Dickens finally completed the subject, gave a more satisfactory answer, welcome friends to guide! The topics are as follows: Add a prototype method to the array local object that is used to delete the

For example, you can query and list duplicate data twice. The code is as follows:Copy code Select * from park_room where parkNum in (Select parkNum from park_roomGroup by parkNumHaving count (parkNum)> 1) Order by parkNum field information description:Park_room -- parking space tableParkNum -- parking space number ExampleRemove duplicate records The code is as follows:Copy code Select count (distin

The following illustration shows today's example: because there is less content, duplicate data can be seen at a glance. Here we will use Excel to test, is it possible to delete the last three rows of duplicate data at once? 1. Position the cursor in the form, switch to the Data tab, and click the Delete Duplicates button in the Data Tools group.

Question: In a sorted list, how to delete duplicate nodes. For example, the following figure: The detailed implementation code is as follows: Delete duplicate node void deleteduplication (listnode** phead) {if (Phead = = NULL | | *phead = NULL) return; listnode* Pprenode = NULL; listnode* pnode = *phead; while (Pnode!= NULL) {ListNode *pnext = pnode->m_pnext; BOOL Needdelete = fals

MySQL has 5 million data, but most of it is repetitive, true on the 1.8 million, so want to how to get these duplicate data out, find a lap on the internet, a lot of it is not in such a code, so inefficient, their own pondering a combination of, find an efficient way to deal with this way, 5 million of data , 10 minutes to remove all repeat, please refer to. Step One: Extract the data_content_152 fields from the 5 million datasheet SFZHM the correspo

Tags: For example, there is now a table of persons (table name: peosons) drop table PERSONS; CREATE TABLE PERSONS (PNAME VARCHAR2, CARDID VARCHAR2 (+), ADDRESS VARCHAR2 (100)); Insert into persons (PNAME, CARDID, ADDRESS) VALUES (' Zhang San ', ' 430682199002121010 ', ' Shenzhen '); Insert into persons (PNAME, CARDID, ADDRESS) VALUES (' John Doe ', ' 430682199002121010 ', ' Shenzhen '); Insert into persons (PNAME, CARDID, ADDRESS) VALUES (' Harry ', ' 430682199002121010 ', ' Shenzhen '); Insert

Background: Today, when I used a crawler to crawl data, I was accidentally suspended when I first crawled data. Later, I started again, but forgot to clear some junk data, as a result, many repeated records are generated in the wordlocation table. The wordlocation table defines the following wordlocation (urlid, wordid, location), where (urlid, wordid) should be unique. Requirements: Remove redundant duplicate data from the wordlocation table Sol

Ideas: Define four nodes, the front node prenode, the current node node, the next node NextNode, delete node Delnode, in the face of the deletion node to ensure that the Prenode connection nextnode to prevent fracture. public static void Deleteduplication (Listnote root) {if (root==null) {return; Listnote prenode=null;//Front node Listnote node=root;//current node while (node!=null) {listnote NE Xtnode=node.getnext ();//Next node Boolean needdelete=false; Determine whether the curren

-->--> (Roy) generation if not object_id (' tempdb ... #t ') is null drop table #t Go CREATE TABLE #t ([num] int,[name] nvarchar (1)) Insert #t Select 1,n ' A ' union ALL Select 1,n ' A ' union ALL Select 1,n ' A ' union ALL Select 2,n ' B ' UNION ALL Select 2,n ' B ' Go Method 1: If object_id (' tempdb.. # ') is not nullDROP TABLE #SELECT DISTINCT * into # from #t--Exclude duplicate record result set generate temp

This is often the case when developing databases:When a piece of data does not exist, insert the data. If the primary key of the data already exists in the database, update the data.How do you do this? First, query data based on the primary key, and then determine whether there is data. If there is data, update the field; otherwise, insert the data.The disadvantage of this is that you need to connect to the database server twice and then use advanced languages to determine whether the logic exis

Microsoft SQL Server tables should not contain duplicate rows and non-unique primary keys. For brevity, in this article we sometimes call the primary key "key" or "PK", but this always represents "primary key". Duplicate PK violates entity integrity and is not allowed in a relational system. SQL Server has various mechanisms for enforcing entity integrity, including indexes, unique constraints, primary KEY

For example:ID Name Value1 a pp2 a PP3 B III4 B pp5 B pp6 C pp7 C pp8 C IIIID is primary keyAsk for such a resultID Name Value1 a pp3 B III4 B pp6 C pp8 C IIIMethod 1Delete yourtablewhere [id] not in (Select MAX ([id]) from yourtableGroup BY (name + value))Method 2Delete aFrom Table a LEFT join (Select (ID) from table GROUP by Name,value) B on A.id=b.idwhere b.id is nullSQL statement for querying and deleting duplicate recordsSQL statement for queryin

Original article: http://support.microsoft.com/kb/139444/SummaryThe Microsoft SQL Server table should not contain duplicate rows and non-unique primary keys. For the sake of conciseness, we sometimes refer to the primary key as "key" or "Pk" in this article, but this always indicates "primary key ". Repeated PK violates entity integrity and is not allowed in the relational system. SQL Server has various mechanisms to enforce entity integrity, includin

MySQL prevent duplicate Insert Record method summaryThere are many ways to prevent MySQL from repeatedly inserting records, usually Ignore,replace,on DUPLICATE KEY UPDATE, which we can also judge in PHP.Scenario One: Using the Ignore keywordIf the uniqueness of a record is distinguished by a primary key primary or a unique index, it is possible to avoid duplicate

Find duplicate data T-SQL in the database ========== first article ============ there are duplicate records under a field in a table, there are many ways, however, there is a method that is relatively efficient. The following statement: Select data_guid from adam_entity_datas A where. rowid> (select Min (B. rowid) from adam_entity_datas B where B. data_guid =. data_guid) if the table contains a large amount

The Microsoft SQL Server table should not contain duplicate rows and non-unique primary keys. For the sake of conciseness, we sometimes refer to the primary key as "key" or "PK" in this article, but this always indicates "primary key ". Repeated PK violates entity integrity and is not allowed in the relational system. SQL Server has various mechanisms to enforce entity integrity, including indexes, unique constraints, primary key constraints, and trig

Although the SQL statements for querying and deleting duplicate records are messy, the content is still good. Although the SQL statements for querying and deleting duplicate records are messy, the content is still good. For example: Id name value 1 a pp 2 a pp 3 B iii 4 B pp 5 B pp 6 c pp 7 c pp 8 c iii Id is the primary key This result is required. Id name value 1 a pp 3 B iii 4 B pp 6 c pp 8 c iii Method

The SQL statement I used: Delete from fp_sgfpxxWhere fphm in (select fphm from fp_sgfpxx group by fphm having count (fphm)> 1)And rowid not in (select min (rowid) from fp_sgfpxx group by fphm having count (fphm)> 1) Delete duplicate invoice numbers SQL statement used to query Repeated Records of multiple fields in the same table From: 7th string For example, there is a personnel table (table name: peosons) Select p1. * from persons p1, per

For example: ID Name Value 1 a pp 2 a PP 3 B III 4 B pp 5 B pp 6 C pp 7 C pp 8 C III ID is primary key Ask for such a result ID Name Value 1 a pp 3 B III 4 B pp 6 C pp 8 C III Method 1 Delete yourtable where [id] not in ( Select MAX ([id]) from yourtable Group BY (name + value) Method 2 Delete a From Table a LEFT join ( Select (ID) from table GROUP by Name,value ) B on A.id=b.id where b.id is null SQL statements for querying and deleting duplicate rec