Question: How do you update duplicate rows in SQL?

How do you update duplicate records in SQL?

12 Answers

UPDATE Table1 SET Column1=Column1+CAST(id AS VARCHAR) WHERE id NOT IN ( SELECT MIN(id) FROM Table1 GROUP BY Column1 ); Input: (1,’A’), (2,’B’), (3,’A’), (4,’C’), (5,’C’), (6,’A’);

Can you update multiple rows in SQL?

Column values on multiple rows can be updated in a single UPDATE statement if the condition specified in WHERE clause matches multiple rows. In this case, the SET clause will be applied to all the matched rows.

How do you update duplicate records in Oracle?

update test_dup set done = ‘error’ where (acc_num,tel_num, imsi) in (select acc_num, tel_num, imsi from test_dup group by acc_num, tel_num, imsi having count(acc_num) > 1); Then it updates 5 rows i.e. all duplicate rows except non-dups.

How do I filter 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.
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How can delete duplicate rows in SQL?

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 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 can I update two rows in one query?

There are a couple of ways to do it. INSERT INTO students (id, score1, score2) VALUES (1, 5, 8), (2, 10, 8), (3, 8, 3), (4, 10, 7) ON DUPLICATE KEY UPDATE score1 = VALUES(score1), score2 = VALUES(score2);

How can I update multiple rows in a single column in SQL?

First, specify the table name that you want to change data in the UPDATE clause. Second, assign a new value for the column that you want to update. In case you want to update data in multiple columns, each column = value pair is separated by a comma (,). Third, specify which rows you want to update in the WHERE clause.

How do you update a loop?

declare begin for i in (select * from emp) loop if i. sal=1300 then update emp set sal=13000; end if; end loop; end; This code is updating all the records with salary 13000.

How do you find duplicate records using analytical functions?

Finding duplicate records using analytic function

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In this query, we added an OVER() clause after the COUNT(*) and placed a list of columns, which we checked for duplicate values, after a partition by clause. The partition by clause split rows into groups.

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. …
  5. Using COUNT(*) = 0 Without Duplicates.

How do I find duplicate rows in SQL using Rowid?

Check for duplicates.

SQL > delete from names a where rowid > (select min(rowid) from names b where and b. age=a. age ); row deleted.

How do you get only one record for each duplicate rows of the ID in SQL?

A few different ways:

  1. SELECT DISTINCT <dup rows> … ; – this will fetch a single row for each set of values.
  2. SELECT … GROUP BY <all the columns selected>; – effectively same as SELECT DISTINCT.
  3. SELECT <dup rows> LIMIT 1; (or however your DB engine implements LIMIT functionality).
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