Question

我正在使用postgres数据库，并且在数据库迁移过程中，我有一个空表tableA，我希望从另一个tableB中存在的数据填充。

CREATE TABLE contributors ( id bigint NOT NULL, pps double precision NOT NULL, contributor_user_id bigint, project_id bigint );包含以下列

tableA

而CREATE TABLE tableA ( id bigint NOT NULL, assigned_ppoints double precision NOT NULL, state integer, contributor_id bigint, project_id bigint );包含以下列

*_id

所有tableB实际上都是外键。

我需要在contributor_id上为project_id和tableA project_id的每个现有组合添加一个新行，如下所示

位于project_id，tableA contributor_user_id
在contributor_id中，我需要tableA

pps

在assigned_ppoints我需要contributor_user_id project_id的{em>总和 state=2 tableA INSERT INTO tableB (id, project_id, contributor_user_id, pps) SELECT MAX(id) FROM tableB, project_id, contributor_id, SUM(assigned_ppoints) FROM tableA WHERE project_id=1 AND state=2 AND contributor_id=1; }}。

我的开始（而且非常遥远）是

project_id

哪个错误，只会添加一行，对应contributor_id和{{1}}的一个组合。

我该怎么做？

Answer 1

Aggregate filter：

Sys.info()
      sysname           release           version          nodename 
    "Windows"        ">= 8 x64"      "build 9200" "DESKTOP-G88LPOJ" 
      machine             login              user    effective_user 
     "x86-64"           "franc"           "franc"           "franc"

对于9.3及以前的版本：

select
    max(id),
    contributor_id,
    project_id,
    sum(assigned_ppoints) filter (where state = 2)
from t
group by 2,3

Answer 2

我建议这样的结构：

insert into A (...)
select
  something_B,
  another_B,
  (select something_C from C where ...) as subselect_C
from B
where ...
;

如您所见，您为B的每个匹配行执行子查询。

将一个唯一键，几列和子查询的总和插入表中

2 个答案: