Only one entry is left for Oracle to delete duplicate data

Source: Internet
Author: User
SQL statement for Oracle query and deletion of duplicate records 1. query for redundant duplicate records in the Table. duplicate records are determined based on a single field (Id). select * from Table whereI

SQL statement for Oracle query and deletion of duplicate records 1. query for redundant duplicate records in the Table. duplicate records are determined based on a single field (Id). select * from table where I

SQL statements used to query and delete duplicate records in Oracle

1. Search for redundant duplicate records in the Table. duplicate records are determined based on a single field (Id ).

Select * from table where Id in (select Id from Table group byId having count (Id)> 1)

2. Delete unnecessary duplicate records in the Table. duplicate records are determined based on a single field (Id), leaving only the records with the smallest rowid

DELETE from table WHERE (id) IN (SELECT id FROM Table group by id having count (id)> 1) and rowid not in (select min (ROWID) FROM table group by id having count (*)> 1 );

3. Search for redundant duplicate records in the table (multiple fields)

Select * from Table a where (a. Id, a. seq) in (select Id, seq from Table group by Id, seq having count (*)> 1)

4. Delete redundant record (multiple fields) in the table, leaving only the records with the smallest rowid

Delete from Table a where (. id,. seq) in (select Id, seq from Table group by Id, seq having count (*)> 1) and rowid not in (select min (rowid) from Table group by Id, seq having count (*)> 1)

5. Search for redundant duplicate records (multiple fields) in the table, excluding records with the smallest rowid

Select * from Table a where (. id,. seq) in (select Id, seq from Table group by Id, seq having count (*)> 1) and rowid not in (select min (rowid) from Table group by Id, seq having count (*)> 1)

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