PostgreSQL中的onflict

PostgreSQL 9.5 引入了一项新功能，UPSERT(insert on conflict do)，当插入遇到约束错误时，直接返回，或者改为执行UPDATE。

1、不存在则插入，存在则更新

insert into test values (1,'test',now()) on conflict (id) do update set info=excluded.info,crt_time=excluded.crt_time; 执行操作：INSERT 0 1 查看结果：select * from test; id | info | crt_time ----+------+---------------------------- 1 | test | 2017-04-24 15:27:25.393948 (1 row) insert into test values (1,'hello digoal',now()) on conflict (id) do update set info=excluded.info,crt_time=excluded.crt_time; INSERT 0 1 查看结果：select * from test; id | info | crt_time ----+--------------+---------------------------- 1 | hello digoal | 2017-04-24 15:27:39.140877 (1 row)

EXCLUDED 代指要插入的记录

2、不存在则插入，存在则直接返回(不做任何处理)

insert into test values (1,'hello digoal',now()) on conflict (id) do nothing; INSERT 0 0 insert into test values (1,'pu',now()) on conflict (id) do nothing; INSERT 0 0 insert into test values (2,'pu',now()) on conflict (id) do nothing; INSERT 0 1 select * from test; id | info | crt_time ----+--------------+---------------------------- 1 | hello digoal | 2017-04-24 15:27:39.140877 2 | pu | 2017-04-24 15:28:20.37392 (2 rows)