Oraclesteps

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 sub-query part makes reference to values from the outer query. ------------------------------------------------------------------------------------------------------------------------------ SELECT...

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 bWHERE a.column1 = b.column1 AND etc...); OR create table testtt (num number);insert into testtt values(111);insert into testtt values(111);insert into testtt values(111);insert into testtt values(111);insert into testtt values(222);insert...

update table_name set (col1,col2,col3)=(select t.col4,t.col5,t.col6 from table_name2 t where something) OR create table tgt ( id number /*primary key*/, x number, y number )/insert into tgt ( id, x, y )select level, level, level from dual connect by level < 4/create table src ( id number /*primary key*/, x number, y number )/insert into src ( id, x, y )select level+1, level*5, level*5 from dual connect by level <...

we can get the last updated date based on the following inbuild function:  scn_to_timestamp(max(ora_rowscn)) Example: create table Test_last_upd (a number, b varchar2(3) ); begin insert into Test_last_upd values (1,'AAA'); insert into Test_last_upd values (2,'BBB'); insert into Test_last_upd values (3,'CCC'); end; update Test_last_upd set b = 'ABC' where a =3; select TLU.*, scn_to_timestamp(max(ora_rowscn)) from...