Can you write a query to find duplicate records in the impertable table?

To find duplicate records in the impertable table, you can use a window function or a GROUP BY approach. Example with a window function:

SELECT *

FROM (

SELECT , COUNT() OVER (PARTITION BY col1, col2, col3) AS dup_cnt

FROM impertable

) t

WHERE dup_cnt > 1;

Replace col1, col2, col3 with the columns that define uniqueness. This returns each duplicate row. If you only need the duplicate keys, use GROUP BY on those columns and HAVING COUNT(*) > 1. Performance depends on indexes; adding a composite index on the key columns speeds up the operation.