SQL DROP or DELETE Table
NOTE: You have to be careful while using this command because once a table is deleted then all the information available in the table would also be lost forever
http://javarevisited.blogspot.com/2012/12/how-to-find-duplicate-records-in-table-mysql-query-example.htmlYou can see in first query that it listed Ruby as duplicate record even though both Ruby have different phone number because we only performed group by on name. Can you please write something about DB performance tuning as well as its being repetitvely asked to me and am unable to convince a great deal as I havent really worked on such scenarios December 17, 2012 at 8:07 AM Anonymous said..
Result set after the usage of ranking function will look as below with all ranks defined 1 for unique values and all duplicates with values greater than 1
How to delete duplicate records using SQL
Delete duplicate records Delete Duplicate Records using SQL By duplicate record I mean that every field in one record is identical to every field in a different record, i.e. To check that you have duplicate records in your table do the following: select count(*) from MyTable and select distinct * from MyTable unfortunately SQL does not permit a select count(distinct)
We extensively use GROUP BY and we all know problem with GROUP BY (We should have all selected column from select clause in group by clause, other wise we cannot use group by). The problem is: the system by mistake inserted duplicate data in R2-R5 (R1 is PK assuem autonumber) and in one of these duplicates R6 and R7 are also filled
sql - removing duplicate rows from a table in DB2 in a single query - Stack Overflow
In order to be able to use a fullselect as the target for a delete clause, it has to match the rules for a deletable view (see "deletable view" under the notes section)
select * from mytable union select * from mytable, thsi query returns the exact records, and i guess we can use this data to build a new table or replacing the previous one. I need to get rid of the duplications, meaning that when names are shown more than once for a given month and year, I only want one of the duplicated intervention records to show up
Remove duplicate records from SQL tables - CodeProject
Assuming that duplicate records might have different fields other than the Primary Key, we will use the MAX aggregate function to select records with maximal values in all fields. License This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL) Share email twitter facebook linkedin reddit google+ About the Author Eugene Ochakovsky Chief Technology Officer Patrol-IT United States No Biography provided You may also be interested in..
Remove Duplicate Rows from a Table in SQL Server - CodeProject
Easiest way to delete more than one duplicate row from a table in SQL Server Introduction Most of the times, we use primary key or unique key for preventing insertion of duplicate rows in SQL Server. Is it too complicated? History 16th February, 2011: Initial post License This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL) Share email twitter facebook linkedin reddit google+ About the Author Sadeque Sharif Software Developer Meridian Group Bangladesh I am: Manager (IT) at Meridian Group
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