CTAS例子

下列範例會為資料表建立名BACKUP為 EVENT _ 的EVENT資料表：

create table event_backup as select * from event;

產生的資料表會繼承資料表中的分佈索引鍵和排序索引鍵。EVENT

select "column", type, encoding, distkey, sortkey
from pg_table_def where tablename = 'event_backup';

column    | type                        | encoding | distkey | sortkey
----------+-----------------------------+----------+---------+--------
catid     | smallint                    | none     | false   |       0
dateid    | smallint                    | none     | false   |       1
eventid   | integer                     | none     | true    |       0
eventname | character varying(200)      | none     | false   |       0
starttime | timestamp without time zone | none     | false   |       0
venueid   | smallint                    | none     | false   |       0

下面的命令EVENTDISTSORT通過從表中選擇四列創建一個名為的新EVENT表。新資料表會依據和排序，EVENTID並依EVENTID下列方式進行分配DATEID：

create table eventdistsort
distkey (1)
sortkey (1,3)
as
select eventid, venueid, dateid, eventname
from event;

結果如下所示：

select "column", type, encoding, distkey, sortkey
from pg_table_def where tablename = 'eventdistsort';

column   |          type          | encoding | distkey | sortkey
---------+------------------------+----------+---------+-------
eventid   | integer               | none     | t       | 1
venueid   | smallint              | none     | f       | 0
dateid    | smallint              | none     | f       | 2
eventname | character varying(200)| none     | f       | 0      

您可以使用分佈和排序索引鍵的資料欄名稱建立完全相同的資料表。例如：

create table eventdistsort1
distkey (eventid)
sortkey (eventid, dateid)
as
select eventid, venueid, dateid, eventname
from event;

以下陳述式會將均勻分佈套用至資料表，但不會定義明確的排序索引鍵。

create table eventdisteven
diststyle even
as
select eventid, venueid, dateid, eventname
from event;

資料表不會繼承 EVENT table (EVENTID) 中的排序索引鍵，因為新資料表已指定EVEN分佈。新資料表沒有排序索引鍵，也沒有分佈索引鍵。

select "column", type, encoding, distkey, sortkey
from pg_table_def where tablename = 'eventdisteven';

column    |          type          | encoding | distkey | sortkey
----------+------------------------+----------+---------+---------
eventid   | integer                | none     | f       | 0
venueid   | smallint               | none     | f       | 0
dateid    | smallint               | none     | f       | 0
eventname | character varying(200) | none     | f       | 0       

以下陳述式會套用均勻分佈，並定義排序索引鍵：

create table eventdistevensort diststyle even sortkey (venueid)
as select eventid, venueid, dateid, eventname from event;

產生的資料表有排序索引鍵，但沒有分佈索引鍵。

select "column", type, encoding, distkey, sortkey
from pg_table_def where tablename = 'eventdistevensort';

column    |          type          | encoding | distkey | sortkey
----------+------------------------+----------+---------+-------
eventid   | integer                | none     | f       | 0
venueid   | smallint               | none     | f       | 1
dateid    | smallint               | none     | f       | 0
eventname | character varying(200) | none     | f       | 0      

下列陳述式會在與傳入資料不同的索引鍵資料行上重新散佈資料EVENT表，而且不會定義任何SORTKEY資EVENTID料行，因此不會排序資料表。

create table venuedistevent distkey(venueid)
as select * from event;

結果如下所示：

select "column", type, encoding, distkey, sortkey
from pg_table_def where tablename = 'venuedistevent';

 column   |            type             | encoding | distkey | sortkey
----------+-----------------------------+----------+---------+-------
eventid   | integer                     | none     | f       | 0
venueid   | smallint                    | none     | t       | 0
catid     | smallint                    | none     | f       | 0
dateid    | smallint                    | none     | f       | 0
eventname | character varying(200)      | none     | f       | 0
starttime | timestamp without time zone | none     | f       | 0