插入表（如果不存在）并在两种情况下都返回ID

你可以做：

with id as (      select id      from table_name      where appid = 2 and name = 'xyz'     ),     i as (      insert table_name (appid, name)          select 2, 'xyz'where not exists (select 1 from id)          returning id     )select idfrom idunion allselect idfrom i;