PostgreSQL upsert:如果字段没有改变,什么都不做

Question

是否可以表达一个upsert查询,如果插入的数据与数据库中已有的数据相比没有任何变化,那么什么都不会发生？

目前我有:

insert into feeds (link, title, category)
values (...)
on conflict (link)
do update set (title, category, _updated)
= (..., now()::timestamp)

Answer 1

您可以where在update零件中添加一个子句:

insert into feeds (link, title, category)
values (...)
on conflict (link)
do update 
   set (title, category, _updated) = (..., now()::timestamp)
where (feeds.title, feeds.category) is distinct from (excluded.title, excluded.category)