这是我的表web_book的方案：
Column | Type | Modifiers
----------------+------------------------+-------------------------------------------------------
id | integer | not null default nextval('web_book_id_seq'::regclass)
page_count | integer | not null
year_published | integer | not null
file | character varying(100) | not null
image | character varying(100) | not null
display_on_hp | boolean | not null
name | character varying(128) | not null
description | text | not null
name_cs | character varying(128) |
name_en | character varying(128) |
description_cs | text |
description_en | text |
该表包含id = 3的一行。我想复制行，但如果我尝试这样：
INSERT INTO web_book SELECT * FROM web_book WHERE id=3;
我得到这个：
ERROR: duplicate key value violates unique constraint "web_book_pkey" DETAIL: Key (id)=(3) already exists
您需要为新插入的行创建一个新的ID：
INSERT INTO web_book(
id,page_count,year_published,file,image,display_on_hp,name,description,name_cs,name_en,description_cs,description_en
)
SELECT nextval('web_book_id_seq'),description_en
FROM web_book WHERE id=3;
如ClodoaldoNeto所提到的，您可以通过简单地省略ID列，让默认定义做到这一点，使事情变得更简单：
INSERT INTO web_book( page_count,description_en ) SELECT page_count,description_en FROM web_book WHERE id=3;
在这种情况下，您不需要知道序列名称(但是这不清楚)。
