[PGS9.2] Example of NULLS {FIRST | LAST ]

/*******************************************************************************
-- Title : [PGS9.2] Example of NULLS {FIRST | LAST ]
-- Reference : postgresql.org
-- Key word : postgresql order by null first last 정렬 우선
*******************************************************************************/

-- Initiate

drop table ttt;

-- create table

create table ttt 

( aa serial not null

, bb varchar(10) null

);

-- load data

insert into ttt(bb)

values ('ggg')

     , (null)

     , ('uuu')

     , ('ddd')

     , ('eee')

     , ('kkk')

     , ('aaa')

     , (null)

     , ('yyy');

-- query table

select * from ttt;

-- using "order by" using nulls first and last

select * from ttt order by bb asc;  /*opposite sql server, same with 'nulls last'*/

select * from ttt order by bb asc nulls first;

select * from ttt order by bb asc nulls last;

select * from ttt order by bb desc;

select * from ttt order by bb desc nulls first;

select * from ttt order by bb desc nulls last;