Tag: Remove duplicate rows
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Remove duplicate rows in Oracle
How to delete all duplicate rows and leave only one of them, in Oracle? DELETE FROM my_table WHERE rowid not in (SELECT MIN(rowid) FROM my_table GROUP BY column1, column2, column3…) ; Where column1, column2, etc. is the key you want to use. Relative links: Remove duplicate rows in MySQL Remove duplicate rows in SQL Server…
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Remove duplicate rows in MySQL
The primary key: id, the unique columns: col_1, col_2, col_3 . You can use a temporary table, like: create temporary table temp_table (id int); insert temp_table (id) select id from your_table t1 where exists ( select * from your_table t2 where t2.col_1 = t1.col_1 and t2.col_2 = t1.col_2 and t2.col_3 = t1.col_3 and t2.id >…
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Remove duplicate rows in SQL Server
Assuming no nulls, you GROUP BY the unique columns (eg. col_1, col_2, col_3), and SELECT the MIN (or MAX) Row ID (eg. row_id) as the row to keep. Then, delete everything that didn’t have a row id: DELETE my_table FROM my_table LEFT OUTER JOIN ( SELECT MIN(row_id) as row_id, col_1, col_2, col_3 FROM my_table GROUP…