sql query to remove duplicates

the data that name does not repeat, then you must use distinct to remove the redundant duplicate records.select DISTINCT name from tableThe resulting results are:NameACIt seems to be working, but what I want to get is the ID value? Change the query statement:SELECT DISTINCT name, ID from tableThe result would be:ID Name1 A2 b3 C4 C5 bWhy doesn't distinct work? The role is actually up, but he also functions

MySQL fuzzy query to remove the space problem?? $sql = "Select MINGC from info WHERE 1=1"; Fuzzy judgment if ($MINGC! = "") { $sql. = "and MINGC like '% $MINGC% '"; } How to remove a space when the name text box blurs a query

Tags: union function combination join like multiple blog multi-column subqueryUnit03:sql (Basic query), SQL (associative query) Column Aliases when the column queried in the SELECT clause is a function or an expression, the name of the field in the result set that is queried is the name of the function or expression.

Remove duplicate records from mongodb group query statistics The mongodb version is, MongoDB shell version: 2.4.4The operating environment and shell window are as follows: [mongo_user@mongodb_dbs ~]# mongo --port 30100MongoDB shell version: 2.4.4connecting to: 127.0.0.1:30000/testmongos> mongos> use posswitched to db posmongos> 1. count the number of group records first, and use the paymentOrder field to g

, we need to take 3rd pages and 5 data entries per page. At this time, we can first remove the data from the first two pages, use top to select the first five data entries. 2. ROW_NUMBER () method This method is supported only from SQL SERVER 2008. Does it feel like it is similar to Oracle ~ -- Second paging query method: ROW_NUMBER () method declare @ pageN

' --true display, false --where birthday> ' 1990-01-01 ' SELECT sex from info WHERE SEX was not NULL SELECT SNAME from info WHERE SNAME like '% Month ' ------back up INFO table to Info--bak --1 Info_bak -- 2 Insert query Data Select *into Intfo_bak from INFO-two functions to create a new table Insert query data --note constraint does not back up identity property backup (Identity) SELECT * into Inf

much.9. Amid the mists and coldest frosts, with barest wrists and stoutest boasts, He thrusts his fists against the posts,And still insists he sees the ghosts. Misty, icy frost, the wrist is empty, the words of the son, saw his fist to the pillar smashed, speak to himself to touch the ghost.10. Badmin was able to beat Bill at billiards and Bill always beat badmin badly at badminton.Badmin can beat bill at billiards, but playing badminton bill often defeats Badmin. 11. Betty beat a bit of butter

Summary of simple SELECT query statements in SQL, and SQL SELECT query statements -- Scott users cannot use it. Use system to log on-- Modify scott account to unlockAlter user scott account unlock;-- Reset the password identified to be recognizedAlter user scott identified by tiger; -- Select the scott user department

Mandatory SQL statement (6) Data Query and SQL statement Data Query 1. Basic Query1) rename a columnSelect name as 'name' from Table name2) define constant ColumnsSelect = 'is 'From table name3) top usage: percent-- In this way, you can obtain the first 20% fields.Select top 20 percent * from Table Name4)

not grant/revoke privileges To/from yourself sql Gt Grant SELECT on dual to public; Grant succeeded. Sql> Select sql_id, address, hash_value, executions, loads, Parse_calls, invalidations 2 from V$sqlarea3 where lower (sql_text) like '%dual% '; sql_id ADDRESS hash_value executions LOADS parse_calls invalidations------------------------------------------ -----------------------------------------gr7s3j0c

MySQL Database Basics (v)--sql query one, single-table query 1, query all fieldsUse the asterisk "" wildcard character in a SELECT statement toquery all fieldsSpecify all fields in the SELECT statementSelect from TStudent ;2. Query the specified fieldQuerying multiple fields

') if exists (SELECT * from tempdb. sysobjects where id=object_id (' tempdb. #Tmp1 ')) drop table #Tmp1Select ID as autoid, * into #Tmp1 from adminif exists (SELECT * from tempdb. sysobjects where id=object_id (' tempdb. #Tmp2 ')) drop table #Tmp2Select min (autoid) as autoid into #Tmp2 from #Tmp1 Group by Username,passwordif exists (SELECT * from dbo.sysobjects WHERE id = object_id (N ' admin ') and objectproperty (Id,n ' isusertable ') = 1) Drop tabl E adminSelect Id,username,password to admi

First the code, you can see the SQL statement to remove duplicate records, get duplicate records Copy Code code as follows: ALTER procedure [dbo]. [Proc_itemmaster_getunique] @PAGEINDEX int, @uid int, @itemnumber varchar (50) As Begin Tran--Start a transaction drop table [Itemmaster]. [dbo]. [Testim]--delete table --Transfer the record to Testim SELECT * into [Itemmaster]. [dbo]. [

One SQL statement is used to remove one MySQL retained. A few days ago, when I made a requirement, I needed to clear repeated records in mysql. The idea was to write them through code traversal, and then I thought it was too complicated, I thought that I should be able to solve the problem through an SQL statement. After checking the information, I have obtained

Tags: SQL statement electronic win style SPAN different statement column DTS --Connect remote SQL or insert data with OPENROWSET --if only temporary access, you can directly use OPENROWSET --Query Example Select * from OpenRowset('SQLOLEDB' ,'SQL Server name';'User name';'Password', database name. dbo. Table name)

-- Simple query -- Projection Query /* Simple query keyword description: All: Specify to display all records, including duplicate rows. All is the default setting. Distinct: displays all records, but does not include duplicate rows. Top n [percent]: Specifies to return the first n rows or the first n % of data records from the result. *: Indicates all records. */

Remove duplicate data Add two fields Alter TableT_employeeAddFsubcompanyVarchar(20); Alter TableT_employeeAddFdepartmentVarchar(20); Assign values to newly added fields UpdateT_employeeSetFsubcompany='Beijing',Fdepartment='Development' WhereFnumber='Dev001'; UpdateT_employeeSetFsubcompany='Shenzhen',Fdepartment='Development' WhereFnumber='Dev002'; UpdateT_employeeSetFsubcompany='Beijing',Fdepartment='Humanresource' W

Huge amount of data (more than million), some of which are all the same, some of the same field, how to effectively remove duplication?If you want to delete the phone (mobilephone), Phone (Officephone), mail (email) at the same time the same data, has been used this statement for deduplication:SQL code Delete From table where ID not in (Select max(ID) from table Group by Mobilephone,officephone,email) Or Delete From

beginning of the duplicates when each of the duplicates in one of the inputs is processed. You can create a unique index to tell SQL Server that there are no duplicate values.If there is a resident predicate, all rows that satisfy the merge predicate will take the value of the resident predicate and return only those rows that satisfy the resident predicate.Merg

Read SQL Server query planRead Catalogue Begin How SQL Server looks for records SQL Server Join method More specific execution procedures Index statistics: The choice of the query plan is based on Optimizing View Queries Recommended Reading-M