1), you can delete them as follows[SQL]View PlainCopy
Select Distinct * to #Tmp from tableName
Drop Table TableName
SELECT * into tableName from #Tmp
Drop Table #Tmp
This duplication occurs because the table is poorly designed and the unique index columns are added to resolve.2, this kind of repetition problem usually requires to keep the first record in the duplicate record, the operation method is as followsSuppose there is a duplicate field name,address, which r
Label:In a database table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct). Keyword DISTINCT is used to return only different values. Table A: 1. Acting on a single rowSelect distinct from A The following results are performed: Acting on multi-column Example 2.1Select distinct from A The following results are performed: In fact, it is the same way that access and SQL Server support it, depending on the name and ID t
Tags: unique values Group Stat author A10 sage how multiple artReference: Http://blog.sina.com.cn/s/blog_6c9d65a10101bkgk.htmlHttp://www.jb51.net/article/39302.htm 1, use distinct to weight (suitable for querying the total number of the whole table)There are multiple schools + teachers to contribute, need to count the total number of authorsSelect COUNT (author) as Total from files each author has a lot of contributions, there are duplicate records here. Select distinct author from files; It is
--Under the sql2005, sql2000 can notCREATE TABLE TB (ID int,name varchar (4))Insert TB Select 1, ' AA 'UNION ALL Select 1, ' AA 'UNION ALL Select 2, ' BB 'UNION ALL select 3, ' BB 'UNION ALL Select 4, ' CC 'UNION ALL Select 1, ' AA 'UNION ALL Select 4, ' CC 'Delete a From(select Id,name,rn=row_number () over (partition by id,name order by ID) from TB) a where rn>1SELECT * FROM TBOriginal: http://blog.csdn.net/hzvcan/article/details/4862927SQL Server Data ded
Tags: mongodbRecently wrote a crawler tool, the data stored in the Web site MongoDB, because the data are duplicated, so I set up the database when the index, the following is my step, the set name is Drugitem,Here is the collection:I want to create a unique index for the name field because I want to ensure that name is not duplicated:In this way I run the program to find that the data is much less than the original set unique index, I carefully review the Discovery program in the Name field is
Business Requirements:A table has the Id,n1,n2,n3 field, which is a new empty table,Table B has id,n1,n2,n3,n4,n5 fields, such as old tables containing data,Now the record of the N1,N2,N3 combination in B table is re-imported into a table, and a table primary key is also entered valueScenario: The records of B table after the query to go to the weight, while the results of the records are numbered, the sequence number as a table to insert the ID value, SQL statement as follows:INSERT INTO A表(id,
The method for de-duplicating Javascript arrays (four methods) and the four methods for de-duplicating Javascript arrays in the example code
Four algorithms to achieve this goal:
Method 1:
Array. prototype. unique1 = function () {var n = []; // a
Repeated items in one-dimensional array:
Use the array_unique function. Use the following example:Copy codeThe Code is as follows:$ Aa = array ("apple", "banana", "pear", "apple", "wail", "watermalon ");$ Bb = array_unique ($ aa );Print_r ($ bb
This article mainly summarizes the three common methods for removing js array duplicates. If you need some help, please refer to them.The first method is more conventional: 1. create a new array to store result 2. in the for loop, an element is
Suppose it is called array $ my_array;Copy codeThe Code is as follows:// Create an empty array.$ Tmp_array = array ();
$ New_array = array ();
// 1. Loop all rows. ($ val is a row)Foreach ($ my_array as $ k => $ val ){
$ Hash = md5 (json_encode ($
The mysql group by statement can be used to deduplicate a column. Directly run the following statement:
Select io_dev_id from io_info where (TID = 1 AND host_name = 'ang1') group by 1;
Deduplicate query by io_dev_id. P: The difference between
This article describes how to deduplicate the number of uuid In the Python statistics file. The example analyzes Python Regular Expression matching and string operation related skills, for more information about how to deduplicate a uuid in a Python
Quick de-duplication analysis of mysql tables with tens of millions of levels bitsCN.com quick de-duplication analysis of mysql tables with tens of millions of levels target: existing tables a and B, merge the data in the two tables to the c table.
Php efficiently removes array duplicates. This article is a simple and efficient code for removing duplicate values from one-dimensional arrays. For more information, see. The code is as follows: Copy the code? Php $ aarray (aCat, bDog, cCat); this
Quick sorting is a basic sorting algorithm. it is quite concise to use Python code, here we will take a look at a simple example of implementing a fast sorting algorithm and removing duplicates in Python: The sorting efficiency is the same as O (N *
My team lead looks like this: array (2) {[14] & amp; gt; array (6) {code ...}} [3] & amp; gt; array (6) {code ...}}} I want to change it to array (2) {[14] & amp; gt; array (6) {code ...}} [3] & amp; gt; array (6) {code ...}}}... my team lead looks
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