Write a query to delete duplicate records in sql

Conclusion During our experience we face situations when we need to clean duplicate values from SQL Server tables.

Delete duplicate rows in mysql

If row number is greater than 1 means it is a duplicate row and to be deleted. ID AND b. From the result of left join, if T. Left join EmpDup table with aliasing table "T" which has lowest "sno" from each duplicates sets. Let's investigate and compare some common ways. The duplicate values can be in the column which will be de-duplicated based on our requirements or the table can contain duplicate rows. In our example assume if EMDup has one more column "hobbies" extra apart from empid , name but you want to delete duplicate records if empid and name are repeated irrespective of "hobbies" data column, in this case Method1 will not work and follow "Method2". By Jagan Mohan Create a table EmpDtl1 with some duplicate rows as shown below to understand different methods of delete duplicate rows. When the loading process completes, table should be cleaned or clean data should be loaded to a permanent table, so after that duplicates are no longer needed. Conclusion During our experience we face situations when we need to clean duplicate values from SQL Server tables.

Check out the examples below to get real world examples on how to delete duplicate records from a table. This is not always the case however.

sql delete duplicate rows but keep original

Let's discuss these cases separately. Solution We will consider two cases in this tip: The first case is when a SQL Server table has a primary key or unique index and one of the columns contains duplicate values which should be removed.

If Rank is greater than 1 means it is a duplicate row and to be deleted. A big table was created and populated as described here: sqlinthewild. One place where the GROUP BY solution might be preferred is situations where a hash aggregate would be chosen in preference to a stream aggregate.

See the below example.

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Delete Duplicate Rows in SQL Server From a Table