How do you delete duplicate rows in SQL Server?

How can I delete duplicate rows in SQL Server?

To delete the duplicate rows from the table in SQL Server, you follow these steps:

  1. Find duplicate rows using GROUP BY clause or ROW_NUMBER() function.
  2. Use DELETE statement to remove the duplicate rows.

How do I delete multiple duplicate records in SQL Server?

You can do with CTE (Common Table Expression).

  1. WITH cte AS (
  2. SELECT empid , name ,
  3. row_number() OVER(PARTITION BY empid , name order by empid ) AS [rn]
  4. FROM dbo.Emp.
  5. )
  6. DELETE cte WHERE [rn] > 1.

How can I delete duplicate rows?

If you want to delete all duplicate rows in the worksheet, just hold down Ctrl + A key to select the entire sheet. 2. On Data tab, click Remove Duplicates in the Data Tools group. Note: With this function, you can also remove rows with the same values in certain columns.

How can I delete duplicate records in SQL Server 2008?

You can remove duplicates by grouping on the thing that is supposed to be unique (whether it be one column or many), then you grab a rowId from each group, and delete everything else besides those rowIds. In the inner query, everything in the table will have a rowId except for the duplicate rows.

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How do I select duplicate rows in SQL?

How to Find Duplicate Values in SQL

  1. Using the GROUP BY clause to group all rows by the target column(s) – i.e. the column(s) you want to check for duplicate values on.
  2. Using the COUNT function in the HAVING clause to check if any of the groups have more than 1 entry; those would be the duplicate values.

How do you eliminate duplicate rows in SQL query without distinct?

Below are alternate solutions :

  1. Remove Duplicates Using Row_Number. WITH CTE (Col1, Col2, Col3, DuplicateCount) AS ( SELECT Col1, Col2, Col3, ROW_NUMBER() OVER(PARTITION BY Col1, Col2, Col3 ORDER BY Col1) AS DuplicateCount FROM MyTable ) SELECT * from CTE Where DuplicateCount = 1.
  2. Remove Duplicates using group By.

How do I remove duplicate rows in select query?

The go to solution for removing duplicate rows from your result sets is to include the distinct keyword in your select statement. It tells the query engine to remove duplicates to produce a result set in which every row is unique. The group by clause can also be used to remove duplicates.

How do you delete one record from duplicates in SQL?

So to delete the duplicate record with SQL Server we can use the SET ROWCOUNT command to limit the number of rows affected by a query. By setting it to 1 we can just delete one of these rows in the table. Note: the select commands are just used to show the data prior and after the delete occurs.

How do you prevent duplicate rows in SQL?

5 Easy Ways How to Avoid Duplicate Records in SQL INSERT INTO SELECT

  1. Adding the Distinct Keyword to a Query to Eliminate Duplicates. …
  2. Using SQL WHERE NOT IN to Remove Duplicate Values. …
  3. Using INSERT INTO WHERE NOT IN SQL Operator. …
  4. Using SQL INSERT INTO IF NOT EXIST. …
  5. Using COUNT(*) = 0 Without Duplicates.
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Does inner join remove duplicates?

Now if I join the table on recid, it will give 0 result, there will be no duplicates because recid is unique. But if I join on firstname and lastname column, which are not unique and there are duplicates, I get duplicates on inner join. The more columns I add on join, the worse it becomes (more duplicates are created).

How do I eliminate duplicate rows in Excel and keep the highest value?

(1) Select Fruit column (which you will remove duplicates rows by), and then click the Primary Key button; (2) Select the Amount column (Which you will keep highest values in), and then click Calculate > Max. (3) Specify combination rules for other columns as you need.

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