I"m testing something in Oracle and populated a table with some sample data, but in the process I accidentally loaded duplicate records, so now I can"t create a primary key using some of the columns.
How can I delete all duplicate rows and leave only one of them?
Use the rowid pseudo column.
DELETE FROM table_name
WHERE rowid not in
GROUP BY column1, column2, column3);
Where column1, column2, and column3 make up the identifying key for each record. You might list all your primary key columns.