Query to Finding and Deleting Duplicate Rows

The following statement will find and display all duplicate rows in a table, except the row with the maximum rowid:

SELECT *

FROM <tableA> a

WHERE rowid  <>  (SELECT max(rowid)

FROM <tableB> b

WHERE a.<column1> = b.<column1>

AND a.<column2> = b.<column2> -- make sure all columns are compared

AND a.<column3> = b.<column3>;

Note:  Duplicate rows which contain only NULL values will not be identified by above statement.