1). 创建"主表"，所有分区都从它继承。
create table ft
(            
sid      int    not null,sdate     date  not null,saddress  varchar(100)
)tablespace tb01;  

2). 创建几个"子"表，每个都从主表上继承

create table ft01 
(check ( sdate >= date '2015-01-01' and sdate < date '2015-02-01') ) 
inherits (ft) 
tablespace tb01;


create table ft02 
( check ( sdate >= date '2015-02-01' and sdate < date '2015-03-01'))
inherits (ft)
tablespace tb01;


create table ft03
( check ( sdate >= date '2015-03-01' and sdate < date '2015-04-01'))
inherits (ft)
tablespace tb01;

create table ft04 
( check ( sdate >= date '2015-04-01' and sdate < date '2015-05-01'))
inherits (ft)
tablespace tb01;


create table ft05
( check ( sdate >= date '2015-05-01' and sdate < date '2015-06-01'))
inherits (ft)
tablespace tb01;

create table ft06 
( check ( sdate >= date '2015-06-01' and sdate < date '2015-07-01'))
inherits (ft)
tablespace tb01;


create table ft07 
( check ( sdate >= date '2015-07-01' and sdate < date '2015-08-01'))
inherits (ft)
tablespace tb01;

create table ft08
( check ( sdate >= date '2015-08-01' and sdate < date '2015-09-01'))
inherits (ft)
tablespace tb01;

create table ft09 
( check ( sdate >= date '2015-09-01' and sdate < date '2015-10-01'))
inherits (ft)
tablespace tb01;


create table ft10
( check ( sdate >= date '2015-10-01' and sdate < date '2015-11-01'))
inherits (ft)
tablespace tb01;


create table ft11
( check ( sdate >= date '2015-11-01' and sdate < date '2015-12-01'))
inherits (ft)
tablespace tb01;


create table ft12
( check ( sdate >= date '2015-12-01' and sdate < date '2016-1-01'))
inherits (ft)
tablespace tb01;


create index index_ft01_sdate on ft01 (sdate) tablespace tb01_index;
create index index_ft02_sdate on ft02 (sdate) tablespace tb01_index;
create index index_ft03_sdate on ft03 (sdate) tablespace tb01_index ;
create index index_ft04_sdate on ft04 (sdate) tablespace tb01_index;
create index index_ft05_sdate on ft05 (sdate) tablespace tb01_index;
create index index_ft06_sdate on ft06 (sdate) tablespace tb01_index;
create index index_ft07_sdate on ft07 (sdate) tablespace tb01_index;
create index index_ft08_sdate on ft08 (sdate) tablespace tb01_index;
create index index_ft09_sdate on ft09 (sdate) tablespace tb01_index;
create index index_ft10_sdate on ft10 (sdate) tablespace tb01_index;
create index index_ft11_sdate on ft11 (sdate) tablespace tb01_index;
create index index_ft12_sdate on ft12 (sdate) tablespace tb01_index;

create or replace function ft_insert_trigger() 
 returns trigger as $$ 
 begin
     if( new.sdate between '2015-1-01' and '2015-02-01' ) then 
         insert into ft01 values (new.*); 
     elsif( new.sdate between '2015-2-01' and '2015-03-01' ) then 
         insert into ft02 values (new.*); 
     elsif( new.sdate between '2015-3-01' and '2015-04-01' ) then 
         insert into ft03 values (new.*); 
     elsif( new.sdate between '2015-4-01' and '2015-05-01' ) then 
         insert into ft04 values (new.*); 
     elsif( new.sdate between '2015-05-01' and '2015-06-01' ) then 
         insert into ft05 values (new.*); 
     elsif( new.sdate between '2015-06-01' and '2015-07-01' ) then 
         insert into ft06 values (new.*);
     elsif( new.sdate between '2015-07-01' and '2015-08-01' ) then 
         insert into ft07 values (new.*);
     elsif( new.sdate between '2015-08-01' and '2015-09-01' ) then 
         insert into ft08 values (new.*);
     elsif( new.sdate between '2015-09-01' and '2015-10-01' ) then 
         insert into ft09 values (new.*);
     elsif( new.sdate between '2015-10-01' and '2015-11-01' ) then 
         insert into ft10 values (new.*);
     elsif( new.sdate between '2015-11-01' and '2015-12-01' ) then 
         insert into ft11 values (new.*);
     elsif( new.sdate between '2015-12-01' and '2016-01-01' ) then 
         insert into ft12 values (new.*);
     else 
         raise exception '!out of range!'; 
     end if; 
     return null; 
 end; 
 $$ 
 language plpgsql;


create trigger insert_ft_trigger 
before insert on ft 
for each row execute procedure ft_insert_trigger() ;


----插入测试数据

insert into ft(sid,sdate,saddress) select n,'2015-01-03',n||':杨楂文'
from generate_series(1,100) n;

insert into ft(sid,'2015-02-04','2015-03-05','2015-04-04','2015-05-05','2015-06-06','2015-07-07','2015-08-08','2015-09-09','2015-10-10','2015-11-11','2015-12-12',100) n;


----查询

 SET constraint_exclusion = off;
 #EXPLAIN SELECT count(*) FROM ft WHERE sdate >= DATE '2015-01-01';  
 
                             QUERY PLAN                            
------------------------------------------------------------------
 Aggregate  (cost=30.02..30.03 rows=1 width=0)
   ->  Append  (cost=0.00..27.01 rows=1202 width=0)
         ->  Seq Scan on ft  (cost=0.00..0.00 rows=1 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft01  (cost=0.00..2.26 rows=101 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft02  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft03  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft04  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft05  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft06  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft07  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft08  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft09  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft10  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft11  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft12  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
(28 rows)



 SET constraint_exclusion = off;
 #EXPLAIN SELECT count(*) FROM ft WHERE sdate >= DATE '2015-01-01';  
 ------------------------------------------------------------------
 Aggregate  (cost=30.02..30.03 rows=1 width=0)
   ->  Append  (cost=0.00..27.01 rows=1202 width=0)
         ->  Seq Scan on ft  (cost=0.00..0.00 rows=1 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft01  (cost=0.00..2.26 rows=101 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft02  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft03  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft04  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft05  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft06  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft07  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft08  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft09  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft10  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft11  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
         ->  Seq Scan on ft12  (cost=0.00..2.25 rows=100 width=0)
               Filter: (sdate >= '2015-01-01'::date)
(28 rows)



# EXPLAIN SELECT count(*) FROM ft WHERE sdate between '2015-03-01' and '2015-04-01'; 
                                       QUERY PLAN                                        
-----------------------------------------------------------------------------------------
 Aggregate  (cost=5.25..5.26 rows=1 width=0)
   ->  Append  (cost=0.00..5.00 rows=102 width=0)
         ->  Seq Scan on ft  (cost=0.00..0.00 rows=1 width=0)
               Filter: ((sdate >= '2015-03-01'::date) AND (sdate <= '2015-04-01'::date))
         ->  Seq Scan on ft03  (cost=0.00..2.50 rows=100 width=0)
               Filter: ((sdate >= '2015-03-01'::date) AND (sdate <= '2015-04-01'::date))
         ->  Seq Scan on ft04  (cost=0.00..2.50 rows=1 width=0)
               Filter: ((sdate >= '2015-03-01'::date) AND (sdate <= '2015-04-01'::date))
(8 rows)