Postgres用returning实现mysql的last_insert_id
Postgres用returning实现mysql的last_insert_id
今天开发问到，postgres里面有没有像mysql那样插入一个值后返回插入的值，这个是有的，而且有更强的扩展性。
示例：
[postgres@localhost ~]$ psql
psql (9.2.4)
Type "help" for help.
postgres=# create table t_kenyon(id int,vname varchar(30),remark text);
CREATE TABLE
postgres=# insert into t_kenyon(id,vname) values(1,'test_kenyon') returning id;
id
----
1
(1 row)
INSERT 0 1
postgres=# insert into t_kenyon(id,vname) select generate_series(1,5),'Kenyon here' returning id;
id
----
1
2
3
4
5
(5 rows)
INSERT 0 5
扩展：
a.返回更多的insert内容
postgres=# insert into t_kenyon(id,vname) select generate_series(6,8),'Kenyon here' returning id,vname;
id | vname
----+-------------
6 | Kenyon here
7 | Kenyon here
8 | Kenyon here
(3 rows)
INSERT 0 3
postgres=# insert into t_kenyon(id,vname,remark) select generate_series(9,11),'Kenyon here','KENYON GOOD BOY!' returning *;
id | vname | remark
----+-------------+------------------
9 | Kenyon here | KENYON GOOD BOY!
10 | Kenyon here | KENYON GOOD BOY!
11 | Kenyon here | KENYON GOOD BOY!
(3 rows)
INSERT 0 3
b.返回delete掉的数据
postgres=# select * from t_kenyon;
id | vname | remark
----+-------------+------------------
1 | test_kenyon |
1 | Kenyon here |
2 | Kenyon here |
3 | Kenyon here |
4 | Kenyon here |
5 | Kenyon here |
6 | Kenyon here |
7 | Kenyon here |
8 | Kenyon here |
9 | Kenyon here | KENYON GOOD BOY!
10 | Kenyon here | KENYON GOOD BOY!
11 | Kenyon here | KENYON GOOD BOY!
(12 rows)
postgres=# delete from t_kenyon where id >9 returning id,vname;
id | vname
----+-------------
10 | Kenyon here
11 | Kenyon here
(2 rows)
DELETE 2
postgres=# delete from t_kenyon where id <5 returning *;
id | vname | remark
----+-------------+--------
1 | test_kenyon |
1 | Kenyon here |
2 | Kenyon here |
3 | Kenyon here |
4 | Kenyon here |
(5 rows)
DELETE 5
postgres=# select * from t_kenyon;
id | vname | remark
----+-------------+------------------
5 | Kenyon here |
6 | Kenyon here |
7 | Kenyon here |
8 | Kenyon here |
9 | Kenyon here | KENYON GOOD BOY!
(5 rows)
c.返回update掉的数据
postgres=# update t_kenyon set remark = 'kenyon bad boy!' where id <7 returning id,remark;
id | remark
----+-----------------
5 | kenyon bad boy!
6 | kenyon bad boy!
(2 rows)
UPDATE 2
mysql的last_insert_id使用有诸多限制和注意的地方，如字段需要auto_increment，一个SQL插入多个值的时候只会返回第一个id值，此不再叙述。
