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Self join is a good option but to have a faster function it is better to first find rows that have duplicates and then join with original table for finding id of duplicated rows. Finally order by any column except id to have duplicated rows near each other.
2 wrz 2020 · Find duplicate values in SQL with ease. This concise guide covers using GROUP BY and HAVING clauses to effectively identify and resolve duplicates.
17 maj 2023 · SQL provides several ways to find duplicates in your data, depending on your requirements and the structure of your tables. You can use the GROUP BY and HAVING clauses to group records by a particular column and filter out duplicates based on a count or condition.
7 lut 2024 · Different ways to find duplicate values in SQL. How to use the DISTINCT, GROUP BY, COUNT, and ROW_NUMBER functions. How to use these functions in query, functions, and other objects to get unique values.
Learn how to identify and list duplicate rows in a SQL table using HAVING, GROUP BY, and JOIN clauses. Follow along with an example query and see the results for the Users table.
SELECT author_last_name, dewey_number, NumOccurrences FROM author INNER JOIN ( SELECT author_id, dewey_number, COUNT(dewey_number) AS NumOccurrences FROM book GROUP BY author_id, dewey_number HAVING ( COUNT(dewey_number) > 1 ) ) AS duplicates ON author.id = duplicates.author_id
You can find duplicates by grouping rows, using the COUNT aggregate function, and specifying a HAVING clause with which to filter rows. Solution: SELECT name, category, FROM product GROUP BY name, category HAVING COUNT(id) > 1;
