SQL

SQL> CREATE SEQUENCE TEST_SEQ_A            START WITH 1            MINVALUE 0            MAXVALUE 1            INCREMENT BY -1  

Sub-query The inner query execute first, the outer query deprnds on inner query output. Correlated sub-query The outer query execute first, the inner query deprnds on outer query result. A correlated sub-query is where the

Use rowid pseudo column. All you have to do is to keep the latest data (i.e. highest ROWID) and remove other duplicated rows. SELECT * FROM table1 a WHERE rowid < (SELECT max(rowid) FROM table1